In the parallel thread where we are discussing audibility of conversion of high resolution audio to CD sampling rate and bit depth, there is a constant set of posts from Ammar (AJ) on audibility issues regarding Amplifiers (see this out of many examples: http://www.hydrogenaud.io/forums/index.php...t&p=882443) (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107124&view=findpost&p=882443)).
I didn't think you all discussed hardware audibility issues in this forum but I am new so perhaps I am mistaken about that. Since the off-topic posts continue to add noise to the other thread, pun intended , I thought we should have a separate thread on them.
If the moderators feel this topic is outside of the scope of the forum, I appreciate all the references in the other thread be deleted and members barred from continued discussion of it there.
So with that intro out of the way, and complying with Forum Terms of Service #8, I present this data from none other but our own Arny Krueger. A bit of back story on this. We were on AVS Forum discussing double blind tests. I realized one day that I have never ever seen Arny post the results of any ABX double blind tests in which he had personally participated. I asked him about it and he said there is only one record of such participation in public. And that was a test of amplifiers published in a now defunct audio magazine some 30 years ago.
I asked Arny for a copy but he said he did not have any to share with us (!). In an ironic turn of event, Arny helped me find a copy of that issue of magazine in an auction which I proceeded to purchase. In that regard I like to thank Arny's kind help in locating that important bit of history.
In order to be sensitive to copyright issues, I am going to post the key parts of the article. It covers almost everything in there as the article is only 2-3 pages long. But should you have more questions I am happy to snip other sections and post. But again, I think you will find these to be a pretty complete picture.
Here is the title of the article:
.
Is it masochism?
Is it masochism?
You have to ask, why would anybody in their right mind try to spin the results of a very straightforward article from several decades back that is based on DBTs against me?
To pursue this logically, there would have to be some place some where I said something like: "All amplifiers sound the same" but I didn't. It is my position that a sufficiently screwed up amplifier can create audible artifacts. The only reason why we had a publishable article (published by 2 independent ragazines on 2 different continents) is because the screwed up amplifier was a product of Audio Reseach, a highly regarded high end audio manufacturer.
OTOH how endangered is the Objectivist's card of someone who mimics your choice of knee jerk high end ragazine reviewers with absurd technical claims like these:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
"
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr
But How Does it Sound?
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
"
Maybe legalization made him forget that embarrassing nonsense he wrote on the Madrona site...and now it's spin control time?
Like him, I'm not even sure what the point is? Amps can sound different???
Is this another Eureka moment, like "OMG, it is possible to muck up 16/44!!!"
cheers,
AJ
Perhaps the first three posters prefer another mudfest, but if not, I suggest that those interested in clarity and efficiency immediately observe the rather sloppy paper conclusion that Amir is (again) pouncing on, and immediately concede that at least one of the amps involved in the referenced test was likely driven beyond its operating limits and thus the likely source of any audible difference. I believe that this has already been acknowledged in one of the mudfests in avsforms, so I don't see the benefit to any (other than those devoted to things other than intellectual honesty and scientific rigor) to replay that here in HA.
Perhaps the first three posters prefer another mudfest, but if not, I suggest that those interested in clarity and efficiency immediately observe the rather sloppy paper conclusion that Amir is (again) pouncing on, and immediately concede that at least one of the amps involved in the referenced test was likely driven beyond its operating limits and thus the likely source of any audible difference.
Not here to discuss "likely." If you have some data to share, by all means do. Throwing FUD on the test results with speculation is not what I consider "science."
As I clearly post, each amplifier was exhibiting 1% distortion:
(http://amirviews.smugmug.com/photos/i-KCSpjj7/0/O/i-KCSpjj7.png)
So they were both equally stressed. The listening level was just 90 db SPL. If you think this is out of norm for a 200 watt amplifier, then you need to make your case to Arny.
I believe that this has already been acknowledged in one of the mudfests in avsforms, so I don't see the benefit to any (other than those devoted to things other than intellectual honesty and scientific rigor) to replay that here in HA.
Can we not have one, just one thread of discussion here where someone doesn't post an emotional rant like this? If you have no interest in the technical topic, then don't engage in it. If you think i am violating forum TOS, report me. If you have references you want to provide from AVS Forum or elsewhere, do so. Otherwise, please save your frustrations, angst, anger, or whatever against any DBT that shows positive outcome. You are contributing to the mudfest in a big way with posts like this, antagonizing members.
So one of the core reasons people go wrong here is the assumption that "clipping" is something that happens when the amp is pushed way beyond its power. Folks imagine these waveforms with flat tops. Reality is very different.
Here is scope snapshot I made of an AVR being pushed with a sine wave:
These circuits can get activated on narrowest peaks in the source content. When they do, the effect is not long lasting and pronounced like above. But rather, momentary creation of non-linear distortions that can color the sound. You would not perceive the harshness you would expect with hard clipping.
Here is another measurement of an AVR that has one channel right before clipping and the other into it:
(http://amirviews.smugmug.com/photos/i-QT2kfMH/0/X2/i-QT2kfMH-X2.png)
Notice the odd distortion exhibiting what I mention above.
OTOH how endangered is the Objectivist's card of someone who mimics your choice of knee jerk high end ragazine reviewers with absurd technical claims like these:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
"
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr
But How Does it Sound?
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
"
If you are going to quote something, you should either quote all of it or indicate you took out something. You did not do either. Here is how the start of that section goes:
But How Does it SoundOK, lots of technical talk but does any of this impact the sound? You may know that there are two schools of thought here. One that says all amplifiers more or less sound the same. The other says the exact opposite with each sounding different like the smell of two different flowers. I won’t take a position in that food fight . But instead, speak of a much less controversial issue of pure power delivery.
This is an informal write up unlike some of my other articles that are published (see http://www.madronadigital.com/Library/Library.html) (http://www.madronadigital.com/Library/Library.html)). I wanted to explain the design of this amplifier and did so. But thought I should share some personal experience. it is subjective and stated as such.
Importantly, I did not state any of this in this forum. AJ went to the web site and post it here. So not sure why you are demanding that I address it.
amir, you're doing yourself no favours at all by doing this. As a bystander who reads this forum you come across as an arrogant bleep. All you seem to want to do is argue with Arny over stuff you either don't understand or disagree with. You've now started two threads purely to argue. Putting smilies all over your posts doesn't somehow make them right or funny, just pathetic.
You obviously have no intention of learning from anyone or taking any point of view except your own so why are you here? You're not engaging in discussion and this is a discussion forum.
Arny, with a great deal of genuine respect, you were obtuse at best in only referring to a "screwed up amplifier (that) was a product of Audio Research" that was apparently never directly and clearly discussed in the paper conclusion mentioned in this thread. But I recall you did acknowledge that clearly in at least a few posts among hundreds of posts elsewhere in at least avsforums.
I gave you another opening, but I'm not going to do your homework for you - please reference or repeat at least the salient posts or information of your previously disclosed info on how you came to believe the AR amp was broken despite the paper conclusion that Amir is going to town on, so that Amir has as little ammo as possible on the general topic of amps and how they sound. You can help shift the discussion at least in this thread if you'd just be clear and concise on exactly what you experienced and learned on the referenced amp test that is not immediately and explicitly obvious from the quoted conclusion that Amir is leveraging.
I have little doubt that Amir is betting that you don't have the energy or humbleness to acknowledge what you already have in other fora on the paper in question - but I hope that you prove him wrong on that.
Wanna give Amir what he wants? Be defensive or obtuse about this. No test or paper is perfect, so acknowledging that is no weakness. Wanna end this thread ASAP to the benefit of all that have a constructive agenda? Please diffuse this with a clear, concise summary of exactly what the AR amp defects were that were not explicitly disclosed in the paper conclusions that Amir is leveraging to troll for the vulnerable.
amir, you're doing yourself no favours at all by doing this. As a bystander who reads this forum you come across as an arrogant bleep. All you seem to want to do is argue with Arny over stuff you either don't understand or disagree with. You've now started two threads purely to argue. Putting smilies all over your posts doesn't somehow make them right or funny, just pathetic.
You obviously have no intention of learning from anyone or taking any point of view except your own so why are you here? You're not engaging in discussion and this is a discussion forum.
Thank you for the feedback. Here is my problem with it and reaction that hopefully you take to heart. If you really mean such things, you should send them privately to me in PM. That you post it here, means it is done for effect as to put me down, under the cover of giving me advice.
I had no intention of creating such a thread whatsoever. AJ has post at least a dozen times if not more in the filter thread asking me about amplifier article on Madrona Web site. Where were good samaritans advising him not to do that as to not reflect poorly on the forum?
Two days ago I reported one of his amplifier posts to the admins. I explained that it is off-topic yet he keeps posting it. No action was taken and he has gone literally crazy posting this stuff over and over again.
Here is one of his posts from yesterday:
I am not a subjectivist
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr
But How Does it Sound?
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
Would love to see you start a thread about "Audibility of Typical Filters in a Class D amp" Amir. You've mentioned TOS #8 a few times, so we know you are aware of it.
cheers,
AJ[/color]
My first post in this forum was a reply to AJ's amplifier post. I had my hand slapped and slapped hard by the admin (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=106442&view=findpost&p=880379). That is within their powers. It is their forum and I am here to follow their rules as strictly as they ask me to do.
So when I see repeated violations of the forum rules above, with demand that I go and create such a thread as otherwise he is going to keep posting nonsense there, I did it. And yes, I did it in a way that puts him in his place. And did so while being 100% compliant with forum TOS. I shared new information, I brought test data that most of you have never seen. Instead of showing interest in that, you rather give me advice in public? And I am supposed to take it as friendly advice? I may be dumb but not stupid .
Let's have whoever else wants to vent, give me advice, discuss world peace, my company's web site, etc. post now and get it out of their system. When you are done, let me know and I can see how I can contribute technically.
Good grief....
Is it masochism?
Did someone say amps
never can sound different?
And does Amir think this is the only article ever published on the subject?
"The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier into a Tone Control?" E. Brad Meyer, Stereo Review, June 1991, page 54
Arny, with a great deal of genuine respect, you were obtuse at best in only referring to a "screwed up amplifier (that) was a product of Audio Research" that was apparently never directly and clearly discussed in the paper conclusion mentioned in this thread. But I recall you did acknowledge that clearly in at least a few posts among hundreds of posts elsewhere in at least avsforums.
One of the odd aspects of this matter is that Amir has a copy of the article that Carlstrom, Greenhill, and I wrote, but I don't. Amir can therefore easily quote the paper to discredit me if I make the slightest mistake or even don't make a mistake but create a gap that Amir can fill with misinterpretations, speculations, and outright distortions of the meaning of various parts of the article.
Proceeding bravely, the story starts in Larry Greenhill's living room in Westchester County, NY many decades ago. It is the Saturday afternoon after I gave a presentation about and demo of ABX to The Audiophile Society at Dr. Hy Kachalsky's house the previous evening. The host's system was notably centerpieced by a Hill Plasmatronics loudspeaker sytem.
Dr. Greenhill introduced the topic of problems reported with the combination of a SS Audio Research D120
(http://www.arcdb.ws/D120/pic.jpg)
and a Acoustat full range electrostatic speaker system
(http://usr.audioasylum.com/images/5/58768/acoustat_modelone_25B15D_28229.jpg) (if memory serves)
We hooked the equipment up and started to listen to it. Greenhill provided us with a certain Eagles LP and instructed us to cue up a certain track and try to crank it up a little. We were rewarded with a fairly horrific crackle on certain bass notes. One of us said something like "That sounds ABX-able" and the test was on.
Greenhill provided a far less expensive and prestigious CM Labs power amp with similar power ratings to compare it to. After carefully matching levels with a voltmeter measuring test tones across the speaker terminals, the ABXing commenced. There was no problem with obtaining statistically significant results.
AJ has post at least a dozen times if not more in the filter thread asking me about amplifier article on Madrona Web site.
By Jove, you've got it (even though you don't)!
Amir, once again, you can't be cognizant of or comprehend any of this, but I'll state it for the record for anyway for others.
The BS paper thread, in the
LISTENING TESTS FORUM was about:
Audibility of Typical Digital Filters in a Hi-Fi Playback System.
Your specious claim is that you can hear deleterious effects of the HF filtering related to 24bit>16/44 downsampling (CD) when "listening".
You then claimed on your website, to be able to hear deleterious effects of the output HF filtering related to Class D amps when "listening"
This is probably impossible for your brain, but are you following so far? Do you see the tie-in..and perhaps why the mods didn't think it was way OT and like one of your many dives into the rabbit hole?
In both instances, you are claiming to "hear" HF output filtering artifacts....except, when the amp costs $50k (2012 pricing)...and oh yes, you happen to sell it.
So...now that we are talking amps/distortion, could you please shed some details on exactly how you "heard" this HF distortion, when not being able to generate ABX logs on your Windows computer?
It seems you used Revel Salons. What sort of listener training was required? Did you adhere to BS-1116? Can we see details of the test setup (like in the M&M and BS paper), the results and how the statistical analysis was done, etc?
Exactly how did you hear the "harshness" in Class D amps vs your $50k MLs free of HF artifacts like a 24bit master?
We'll get to the preposterous claims you made about linear vs SMPS later.
cheers,
AJ
We hooked the equipment up and started to listen to it. Greenhill provided us with a certain Eagles LP and instructed us to cue up a certain track and try to crank it up a little. We were rewarded with a fairly horrific crackle on certain bass notes. One of us said something like "That sounds ABX-able" and the test was on.
Hi Arny. Thank you for filling the details for us. I am curious why any ABX testing was needed if an amplifier is having "fairly horrific crackle?" Is that the kind of artifact that is subject to placebo?
As I quoted from the article, it says that you use an oscilloscope to measure clipping and it was around 1% on *both* amplifiers. Does 1% clipping create horrific cracking sound?
Greenhill provided a far less expensive and prestigious CM Labs power amp with similar power ratings to compare it to. After carefully matching levels with a voltmeter measuring test tones across the speaker terminals, the ABXing commenced. There was no problem with obtaining statistically significant results.
One would think so with any horrific distortion . I don't see a step where an oscilloscope was used. Given the statistical nature of the distortion percentage, I assume that was with real music and some kind of internal instrumentation of each amplifier which would be quite a bit more involved than what you are describing.
But yes, you are right that your subjective observations don't match the article .
Thanks again.
Is it masochism?
Did someone say amps never can sound different?
There is a wide gulf between that, and actually posting positive double blind ABX tests of two powerful solid state amplifiers. If someone showed up and said those two amps sounded different to them you guys would take away all of his credentials, take his cloths off, and leave him naked in the desert. So let's dispense with that tactic of "who said they don't." You all do. Or else folks wouldn't have resentment to this thread. And Arny's work including Arny himself.
And does Amir think this is the only article ever published on the subject?
"The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier into a Tone Control?" E. Brad Meyer, Stereo Review, June 1991, page 54
More the better. Please post whatever you think is relevant to this thread. Hopefully it is not some tube amp compared to solid state and such.
Amir, please don't play with matches. The amount of straw you're building up is dangerous.
So this thread will have nothing to do with audibility of amplifier distortion. Something, like in the other thread, you have made very specific claims to be able to hear-"listen" for (Class D filtering and PS).
Just like the other thread, zero ability to demonstrate your spurious claims.
Let's see if we can spin for 28 pages.
cheers,
AJ
We'll get to the preposterous claims you made about linear vs SMPS later.
Let's have it.
If you really mean such things, you should send them privately to me in PM. That you post it here, means it is done for effect as to put me down, under the cover of giving me advice.
I'm not giving advice, I think you're an arrogant bleep who's only purpose on this forum from what I've read is to disagree with people and not to pay any attention to anything anyone says. Not sure I can put it more plainly than that.
I am curious why any ABX testing was needed if an amplifier is having "fairly horrific crackle?" Is that the kind of artifact that is subject to placebo?
Of course, and only a still-naive subjectivist could suggest otherwise given years of posting on consumer oriented audio forums. The pros can be no different.
People get obsessed with small audible differences whether they are real or illusions. They get blown way out of proportion. "The difference due to cable dielectric is so great that my wife hears it in the kitchen." In that regard I am no better than any other audiophile or pro - I can become obsessed with small, even imaginary audible differences and blow them way out of proportion in my mind.
I invented the ABX Comparator as a mental prosthesis to help me behave sanely and rationally.
Was the crackle really horrific? I'll bet a lot of people would have never noticed it.
The main difference between objectivists and subjectivists in audio is that objectivists can actually entertain the possibility that things may not be exactly as they perceive them. They can have insights into their thoughts and actions. They have a choice other than to take everything at face value. That means that they can actually behave like a sane adult with respect to audio.
We'll get to the preposterous claims you made about linear vs SMPS later.
Let's have it.
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimeh
"While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. "
Because of my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS.
In addition I have some background with after market car audio, whose power amplifiers have long made heavy use of SMPS.
The following statement is denied by facts accessible to everybody who has enough electrical engineering talent to read the required plain English labeling of the SMPS wall warts that are endemic today: "... power supply voltage variations and noise which unfortunately get worse with switching supplies. "
Just read the label! For example the SMPS for this (and virtually every other) laptop is rated for input voltages from 100 to 240 volts (or an even wider range). This one has a rated output voltage of 20 volts and were one to be technical enough to measure it, one would find that it has good regulation with respect to input voltages and changes in load. It also has low output and radiatednoise - legally mandated by FCC Part 15.
Modern SMPS power supplies are vast improvements over their linear predecessors. A typical linear iron transformer-and-diode wall wart rated at say 9 volts had such poor regulation that it would put out more like 12 volts with no load and might barely make 9 volts with rated load, or not. This presumes a predictable and stable power line which may not be the case. It also produced massive amounts of noise in its output because unlike the SMPS this was not a federally-mandated parameter (FCC Part 15). The simple brute force single capacitor filter if present allows volts of ripple noise when the current drain goes up.
Virtually every switchmode power amplifier on the market today has a SMPS power supply. They sacrifice no sound quality because of it.
I speculate that the Levinson 53 has a linear power supply because some marketing person decided that they needed to pander to audiophile hysterical fear of modern technology, particularly SMPS.
Please notice that this official document from Levinson seems to fail to make the above false claims:
http://www.marklevinson.com/tl_files/catal...010_5.17.10.pdf (http://www.marklevinson.com/tl_files/catalog//Mark%20Levinson/Manuals/No53/prod_22_634473655136955941_ML%20No53%20Technology%20Background%20V5%2004032010_5.17.10.pdf)
The false claims in the Madronna article are likely the invention of its author.
Let's have it.
Ok Amir, here goes. You ready?
Happy Thanksgiving.
If you really mean such things, you should send them privately to me in PM. That you post it here, means it is done for effect as to put me down, under the cover of giving me advice.
I'm not giving advice, I think you're an arrogant bleep who's only purpose on this forum from what I've read is to disagree with people and not to pay any attention to anything anyone says. Not sure I can put it more plainly than that.
Ah, in that case I take back my "thank you" in my response to you .
As to your specific commentary, I present to you this short video from one of my all time favorite movies, My Cousin Vinny:
https://www.youtube.com/watch?v=v4KR1zVqizo (https://www.youtube.com/watch?v=v4KR1zVqizo)
This is a technical topic. If you have some rants about me, please create a separate topic and post it there. You are antagonizing the membership with off-topic personal insults like that.
Let's have it.
Ok Amir, here goes. You ready?
Sure.
Happy Thanksgiving.
Same to you Ammar and the rest of the membership in US.
Because of my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS.
??? Please forgive me Arny for being blunt but that is like the gas station attendant saying he is intimately familiar with the engine in your car because he has put gas in thousands of cars . All you need there is a screwdriver to bolt a power supply to a PC case. And plugging in its cable into the motherboard. That gives you no understanding of how PC switchmode power supplies work. My kids in elementary school were building their PCs and I am pretty sure they, nor their friends had any idea how they worked.
The discussion here is about class D amplifiers. Contrary to popular myth, class D does not mean "Digital." The letter D was just the next one in the alphabet. So you working with mainframe computers gives you no familiarity whatsoever with the design of class D amplifiers.
As you may recall, you and I had a conversation about amplifiers design on AVS Forum. There you proceeded to explain the schematic of Bryston power amplifier only to confuse the control microprocessor schematic with the power supply! https://www.google.com/url?sa=t&rct=j&a...Fji7W--NGJ4qhIg (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAA&url=http%3A%2F%2Fwww.avsforum.com%2Fforum%2F91-audio-theory-setup-chat%2F1492314-question-bi-amping-17.html&ei=V0V3VK6SPITzoASKvICwBg&usg=AFQjCNF_x538zEd7AgdzMp5WNTEyVbgERw&sig2=zteEjUbFji7W--NGJ4qhIg)
You were kind enough to admit that: http://www.avsforum.com/forum/91-audio-the...ml#post23981673 (http://www.avsforum.com/forum/91-audio-theory-setup-chat/1492314-question-bi-amping-17.html#post23981673)
Yes, I misread the schematic which is really disappointing.
Let's have AJ sleep in the bed he has made and explain what he meant with that bold statement.
Happy thanksgiving Arny.
Because of my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS.
??? Please forgive me Arny for being blunt but that is like the gas station attendant saying he is intimately familiar with the engine in your car because he has put gas in thousands of cars .
For opener's Amir your unfounded, unwarranted, egregious personal insults skip over most of just the fraction of my response that you quoted out of context.
Secondly a gas station attendant need not have the skills to build or maintain a car. Your example doesn't fit.
All you need there is a screwdriver to bolt a power supply to a PC case. And plugging in its cable into the motherboard.
The above has got to be very funny for people who actually know the right answer to this question. Installing a PC power supply takes a lot of more than plugging a cable. For example the power supply needs to be appropriate for the application which involves power levels ranging from a bout 65 watts to over 500 watts. There are a number of form factors, and there are some that run directly off of 12 car power. For example, the interface between a PC power supply and the motherboard in a typical modern PC requires 2 or 3 different cables in addition to the power cord which you missed. Thirdly, power cables have to be run to the disc drives, and may video cards have their own power cables that run back to the power supply. There may be a dozen or more different plug formats, and some of them supply the same power, so you have to know which goes to which. Not rocket science but not the dumbed down version you came up with!
Bottom line Amir while it is true that a smart high school kid can sometimes successfully build a PC without help, you have shown above how you lack even those basic skills.
That gives you no understanding of how PC switchmode power supplies work.
Well Amir, you have conclusively proven that you are way behind me in that area. Way to go! ;-)
All of your false claims above still don't answer any of the errors that I found in that incompetent golden ear fluff piece I found about the Levinson 53 at your corporate web site.
My kids in elementary school were building their PCs and I am pretty sure they, nor their friends had any idea how they worked.
In elementary school the kids get something that you obviously lack Amir, and that is adult supervision. ;-)
Have a nice Thanksgiving Amir, and no extra charge for the obviously much needed instruction in how to put a power supply into a PC.
Because of my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS.
??? Please forgive me Arny for being blunt but that is like the gas station attendant saying he is intimately familiar with the engine in your car because he has put gas in thousands of cars .
For opener's Amir your unfounded, unwarranted, egregious personal insults skip over most of just the fraction of my response that you quoted out of context.
Arny, I didn't ask you to reply or provide your resume. You did both so I commented on them. What you listed are not remotely qualifications to understand a switchmode power supply. This type of power supply is extremely complicated to design/understand even for experienced analog designers. When I was at Sony and wanted to hire an engineer to design our laptop power supply, I interviewed a ton of analog designers. None knew even the most fundamental issues in designing them. If they are not qualified to speak to this topic, surely someone who has just put PCs together and worked on mainframe computers is not remotely qualified to talk about them.
And that is just the power supply. Here we are talking about the performance of switchmode power supplies as it applies to class D amplifiers. This is a whole other game requiring even more advanced knowledge than a power supply designer. All you have demonstrated so far is that you know how to open the case on a power supply. That gives you no qualifications to comment on this complex topic.
Bottom line Amir while it is true that a smart high school kid can sometimes successfully build a PC without help, you have shown above how you lack even those basic skills.
There we go. We would not engage said high-school kid on design ramifications of switchmode power supplies in class D amplifiers. So you saying that qualifies you to speak on this topic is like the analogy I gave. Skills in assembling computers gets you a minimum wage job here, not anything remotely qualified to speak to topic at hand.
so let's see.....
Amir trumpets an old obscure article by Arny (his personal bete noir) & Co that seems to be comparing two amps, at least one of which had 'problems'.....
He admits he's never heard of or read a rather more widely read article, in Stereo Review (then a mass market newsstand magazine popular with audio fans), from 1991 by E. Brad Meyer, describing load conditions under which two amps will sound different.....
All the while, across multiple websites and threads therein he makes of habit of putting people down* in the guise of 'educating' them from his expert** POV...
And then complains here that posts critical of him have the intent of 'putting me down under the cover of giving me advice'....
Is this guy a piece of work, or what?
____
*including....E. Brad Meyer!
** expert at googling, that is
Because of my professional experience with computers particularly mainframe computers going back to 1965 I have long been intimately familiar with SMPS. I've also built thousands of PCs and every one had a SMPS.
??? Please forgive me Arny for being blunt but that is like the gas station attendant saying he is intimately familiar with the engine in your car because he has put gas in thousands of cars .
For opener's Amir your unfounded, unwarranted, egregious personal insults skip over most of just the fraction of my response that you quoted out of context.
Arny, I didn't ask you to reply or provide your resume. You did both so I commented on them.
False claim. Calling a few comments about my experiences with SMPS a resume just shows how desperate some people can become to distract attention from their egregious false claims such as:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/Mark...3Amplifier.html)
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimeh
"While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to
power supply voltage variations and noise which unfortunately get worse with switching supplies. "
Amir, instead of sticking your nose where it doesn't belong, why don't you concede the point or provide believable evidence that switchmode power supplies a
lways makes amplifiers perform audibly worse which is your basic claim, above.
If you could provide reliable evidence that SMPS are as bad as you say with swichmode power amps, people around here who recommend and use them with switchmode power amps could be put back on the road to audio nirvana.
so let's see.....
Yes, let's....
Amir trumpets an old obscure article by Arny (his personal bete noir) & Co that seems to be comparing two amps, at least one of which had 'problems'.....
Wow, how far we have come. This is a forum that prides itself on requirement for providing double blind evidence of audibility. Now posting about such evidence is a sin! Why? Because it has a positive outcome.
The support for forum TOS #8 seems to have stemmed from the expectation that all double blind tests of such would result in negative outcome. I can't rationalize commentary like Steven's any other way.
That aside, that test is obscure because until I bought a copy and quoted it online, no one in any of these forums had seen or read it. Even AES papers claiming to be rounding up amplifier tests did not reference this work where positive identification occurred.
Hopefully with threads like this we increase its visibility and take it out of obscurity status.
He admits he's never heard of or read a rather more widely read article, in Stereo Review (then a mass market newsstand magazine popular with audio fans), from 1991 by E. Brad Meyer, describing load conditions under which two amps will sound different.....
Come again? You made a reference to that article. I asked you to quote what you think is relevant to this thread. You turn that into me not having the article? What does that have to do with you putting it forward as evidence?
As it turns out, I do have the article . Let me quote a relevant section from it:
(http://amirviews.smugmug.com/photos/i-Jt5fNnD/0/XL/i-Jt5fNnD-XL.png)
Recall what Arny said about his testing:
(http://amirviews.smugmug.com/photos/i-KCSpjj7/0/O/i-KCSpjj7.png)
So the distortion level was not "well over 1%." Meyer says that shouldn't be audible failing to know about Arny and Crew's listening test 9 years prior disputing the same.
All the while, across multiple websites and threads therein he makes of habit of putting people down* in the guise of 'educating' them from his expert** POV...
And then complains here that posts critical of him have the intent of 'putting me down under the cover of giving me advice'....
Is this guy a piece of work, or what?
Once more I am going to request that members stay focused on the technical topic and not discuss me personally. Right now you are in the hot seat Steven. You referenced an article you are quoting. Claimed i don't have a copy of the article which I clearly do. I have quoted a section from it that disputes your notion that there is nothing new in Arny and friend's test. Arny's test showed audibility at 1% distortion and Meyer says that is not supposed to be audible. You have an answer for this?
so let's see.....
Yes, let's....
Amir trumpets an old obscure article by Arny (his personal bete noir) & Co that seems to be comparing two amps, at least one of which had 'problems'.....
Wow, how far we have come. This is a forum that prides itself on requirement for providing double blind evidence of audibility. Now posting about such evidence is a sin! Why? Because it has a positive outcome.
The support for forum TOS #8 seems to have stemmed from the expectation that all double blind tests of such would result in negative outcome. I can't rationalize commentary like Steven's any other way.
That aside, that test is obscure because until I bought a copy and quoted it online, no one in any of these forums had seen or read it. Even AES papers claiming to be rounding up amplifier tests did not reference this work where positive identification occurred.
Hopefully with threads like this we increase its visibility and take it out of obscurity status.
He admits he's never heard of or read a rather more widely read article, in Stereo Review (then a mass market newsstand magazine popular with audio fans), from 1991 by E. Brad Meyer, describing load conditions under which two amps will sound different.....
Come again? You made a reference to that article. I asked you to quote what you think is relevant to this thread. You turn that into me not having the article? What does that have to do with you putting it forward as evidence?
As it turns out, I do have the article . Let me quote a relevant section from it:
1% of the time is not 1% distortion. If it is 100% distortion 1% of the time, you'll hear it
Hehe . I stand corrected. And present this other evidence from Arny's test:
. Should have been inaudible according to Meyer. Steven, what say you?
False claim. Calling a few comments about my experiences with SMPS a resume just shows how desperate some people can become to distract attention from their egregious false claims such as:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/Mark...3Amplifier.html)
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimehr
"While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. "
Amir, instead of sticking your nose where it doesn't belong, why don't you concede the point or provide believable evidence that switchmode power supplies always makes amplifiers perform audibly worse which is your basic claim, above.
My write-up above is specific to class D amplifiers Arny. Your comment broadens it to all amplifiers.
If you could provide reliable evidence that SMPS are as bad as you say with swichmode power amps, people around here who recommend and use them with switchmode power amps could be put back on the road to audio nirvana.
I have not offered my write up to this forum/thread. You are putting it forward. So you need do as AJ said he would do: demonstrate technically what is wrong with that statement. Please walk us through what you know of Class D amplifier designs and the relationship to its power supply.
If you can't say what is wrong with that statement technically, then we are done. So far you have told us you build PCs and worked on mainframe computers. And some hobbyist unrelated talk about wall wart power supplies. We are discussing Class D amplification and how to power them. Do you have anything technical/references to provide there Arny?
Oh how quaint. Amir 'found' the E. Brad Meyer article that he must have 'forgotten' before, when he evinced no clue as to its existence. An article by the guy he says isn't really authoritative enough to write articles like Meyer & Moran 2007. Well, that's nice. He's reviewed it carefully and pulled one line from it and now he accepts EBM's authority, which he interprets as saying: only having >>1% 'ordinary harmonic distortion' makes amp differences audible. Arny & Co's amps didn't have that, therefore amps sound different because of.... magic reasons, I guess.
Everyone here is on to him, as I expected they would be.
Oh how quaint. Amir 'found' the E. Brad Meyer article that he must have 'forgotten' before, when he evinced no clue as to its existence. An article by the guy he says isn't really authoritative enough to write articles like Meyer & Moran 2007.
He is not authoritative there, or here. Who says this is true:
(http://amirviews.smugmug.com/photos/i-Jt5fNnD/0/XL/i-Jt5fNnD-XL.png)
Where is the double blind test to demonstrate that?
Well, that's nice. He's reviewed it carefully and pulled one line from it and now he accepts EBM's authority, which he interprets as saying: only having >>1% 'ordinary harmonic distortion' makes amp differences audible. Arny & Co's amps didn't have that, therefore amps sound different because of.... magic reasons, I guess.
Oh, I will pull more lines out of it. You can be sure of that. You should read and understand what you introduce to a thread. When you don't do that you get hit on the nose with your own witness statement.
As to your comment, per above I don't buy the speculation from Meyer on THD distortion as it fails the most fundamentals of psychoacoustics. THD is psychoacoustically blind performance measure and has no place whatsoever in the context of audibility of distortion. That he uses it to make a point like yet again shows that he is the wrong messiah for objectivity camp.
I put it forward since you offered it as a trusted reference that easily runs foul of Arny's listening test. So now you have to take sides, telling us who you think is right: Arny and his test or Meyer.
Everyone here is on to him, as I expected they would be.
Likewise yet again you are full of anger and frustration, but short on any technical contributions. Can we expect your next post to not be information-free like this one?
Where is the double blind test to demonstrate that?
What is the null hypothesis?
Is this one, reporting amplifier ABX results from trials conducted by David Clark, also in Amir's collection?
"Do All Amplifiers Sound the Same?", Masters, Ian G., Stereo Review, Jan 1987, pg 78-84.
Or most of the list below, for that matter (which includes the three papers mentioned so far)? It's not like the topic of amplifier difference has never been written about before. I've got copies of a lot of them. One would think that anyone who is interested in this stuff very much, would. They wouldn't want to be re-inventing the wheel.
One would think.
But I do so enjoy providing educational resources to the needy such as Amir.
-References (http://2eyespy.tripod.com/id5.html)-
"Topological Analysis of Consumer Audio Electronics: Another Approach to Show that MOdern Audio Electronics are Acoustically Transparent", Rich, David and Aczel, Peter, 99 AES Convention, 1995, Print #4053.
"The Great Debate: Is Anyone Winning?", Nousaine, Tom, Proceedings of the AES, 8th International Conference, 1990.
"Audiolab Test: Six Power Amplifiers", Masters, Ian G., Audio Scene Canada, May 1977, pg 44-50.
"Audiolab Test: Amplifiers and Speaker Cables", Masters, Ian G., Audio Scene Canada, Jun 1981, pg 24-27.
"Do All Amplifiers Sound the Same?", Masters, Ian G., Stereo Review, Jan 1987, pg 78-84.
"Audible Amplifier Distortion is not a Mystery", Baxandall, Peter J., Wireless World, Nov 1977, pg 63-66.
"Amplifier Tests on Test-2, The Panel Game", Colloms, Martin, Hi-Fi News & Record Review, Nov 1978, pg 114-117.
"Amplifier Tests on Test-1, Without Prejudice", Hope, Adrian, Hi-Fi News& Record Review, Nov 1978, pg 110-113.
"Positive Feedback: Rational Amplifier Testing", Walker, P. J., Hi-Fi News & Record Review, Jul 1977, pg 135.
"Some Amplifiers Do Sound Different", Carlstrom, D., Kruger, A., & Greenhill, L., The Audio Amateur, 3/1982, pg 30, 31.
"Equipment Profile", Greenhill, L. & Clark, D., Audio, Apr 1985, pg 56-60, 82-97.
"Power Amplifiers and the Loudspeaker Load",Johnson, J. H., Audio, Aug 1977.
"Amplifier Design & Sound Quality", Holman, Tomlinson, Audio, Nov 1996, pg 26-31.
"The Amp/Speakers Interface, are your Loudspeakers turning your amp into a Tone Control?", Meyers, E. Brad, Stereo Review, Jun 1991, pg 53-56.
"Audio Power Amplifiers for Loudspeaker Loads", Benjamin, Eric, Journal of the Audio Engineering Society, vol 42, No. 9, Sep 1994, pg 670-683.
"A New Look at Medium and High-Priced Power Amplifiers", Rich, David, The Audio Critic, #20, Summer 93, pg 14.
"Reasonably Priced Pre amplifiers for the Reasonable Audiophiles" Rich, David, The Audio Critic, #18, Spring/Summer 1992.
Amp Tests, Boston Audio Society Speaker, Vol 21, No.2, pg 18-20, Sep 1997.
//
PS. Amir can read these for extra class credit:
the well-known, long and considered, but ultimately inconclusive, essay by Rod Elliot
http://sound.westhost.com/amp-sound.htm (http://sound.westhost.com/amp-sound.htm)
and Roger Russell's amusing and also well-known (to those in the trenches) 'Audio Distortions' page, which includes an anecdote about hjis own ABX of amplifers
http://www.roger-russell.com/truth/truth.htm (http://www.roger-russell.com/truth/truth.htm)
Warm up your highlighter, Amir! There may be pop quizzes on the material!
Warm up your highlighter, Amir! There may be pop quizzes on the material!
Steven, I am going to ask you directly and specifically: do you have the Meyer article that you asked me about? I searched online and every reference with your name simply threw out the title as you did here, not quoting a single thing. Of course I may have missed it.
Can you point to a reference some place where you have directly quoted this article?
"The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier into a Tone Control?" E. Brad Meyer, Stereo Review, June 1991, page 54
Warm up your highlighter, Amir! There may be pop quizzes on the material!
Steven, I am going to ask you directly and specifically: do you have the Meyer article that you asked me about?
Yes,I do and have done, for years. It was available online for years, too, and I've linked to it in the past. The article is gone now from the Internets and has been for some time, alas. Perhaps I will remedy that the next time I'm near a scanner.
Pop quiz! Please identify the *page number* where each snippet occurs:
1. "...tube amplifiers (and solid-state amps designed deliberately to behave like tube amps) will tend to behave differently...."
2. "...to this day, no one has been able to do it, except under special conditions...."
3." ...looks like we should buy the transistor amplifier because its response is flatter...."
4. "...amplifiers cost thousands off dollars, and people buy them....."
5. "...an upward tilt below 500Hz that gave the tube amplifier a warmer overall tone..."
You will not be graded on a curve.
Btw, next time, please raise you had before you shout out a question in class, or you will be sent away for a time-out.
Pop quiz! Please identify the *page number* where each snippet occurs:
1. "...tube amplifiers (and solid-state amps designed deliberately to behave like tube amps) will tend to behave differently...."
2. "...to this day, no one has been able to do it, except under special conditions...."
3." ...looks like we should buy the transistor amplifier because its response is flatter...."
4. "...amplifiers cost thousands off dollars, and people buy them....."
5. "...an upward tilt below 500Hz that gave the tube amplifier a warmer overall tone..."
You will not be graded on a curve.
Let me help you with the out of context quote in #3 Steven:
.
But I do so enjoy providing educational resources to the needy such as Amir.
-References (http://2eyespy.tripod.com/id5.html)-
Thanks for the reference Steven. Alas, you are just cutting and pasting some poor guy's web site. What is the point in that?
While there, I took a look at his home page and saw his gear: http://2eyespy.tripod.com/index.html (http://2eyespy.tripod.com/index.html)
. A taste of that below.
PS. Amir can read these for extra class credit:
the well-known, long and considered, but ultimately inconclusive, essay by Rod Elliot
http://sound.westhost.com/amp-sound.htm (http://sound.westhost.com/amp-sound.htm)
Did you read this part Steven?
"If THD is quoted without reference to its harmonic content, then it is quite possible that two amplifiers may indicate identical distortion figures, but one will sound much worse than the other. "Precisely what I said about the mistaken remark from Meyer regarding THD as a metric/threshold for distortion.
But yes, that is a great reference and I have read every page there and some multiple times. Alas if you are not an analog electrical engineer/designer you will get lost and lost quick.
and Roger Russell's amusing and also well-known (to those in the trenches) 'Audio Distortions' page, which includes an anecdote about hjis own ABX of amplifers
http://www.roger-russell.com/truth/truth.htm (http://www.roger-russell.com/truth/truth.htm)
So you approve of these few paragraphs?
"If you have only heard one CD player, you may have enjoyed all of the advantages without being aware that there are still differences. In an A-B comparison, response is the same, even when compared with a steady source such as pink noise. Harmonic and intermodulation distortion are so low that the players all sound very clean.
The difference is something new and may require a readjustment to know what to listen for. The difference is in imaging. It is most easily heard using speakers that have exceptional imaging capabilities, like my new speaker system. However, regardless of what speaker is used, it is almost impossible to convey a listening experience in words. Nevertheless, I will try to describe what I have heard. I have used a McIntosh MCD7005, McIntosh MVP851and a McIntosh MVP851 supplemented with a McIntosh MDA1000 digital to analog converter for the listening tests. I made these tests in late 2004 and early 2005. My listening was done in two different ways. The first was in instant switching between the two choices and the second was long term listening to each.
Imaging using the 7005 appears to be very wide with orchestral music but there was separateness of the sound with the left and right speakers. I had always assumed this was the way the recordings were made. On the other hand, some new age recordings seemed to completely envelop the listener. That was very pleasing. It was only when I began using the 851 that I noticed there was a difference in imaging. Classical music sounded like it had much better coherence and less separateness, giving it more clarity and sense of aliveness. However, it was more than just imaging. It was a new kind of distortion difference, more like a phase distortion of some kind that affected the coherence of the image. The 851 was made in 2004 and the older 7005 was made in 1987.
The explanation had a definite physical cause. It was the digital-to-analog filtering. "Maybe I should quote him the Stuart thread if you think this is authoritative. It fully supports the work there of finding differences in filters.
On amplifiers, he has this to say:
When Good Amplifiers Can Sound Different
Transients
Another factor related to ringing and oscillation is transients. This determines how well an amplifier with extended bandwidth can reproduce waveforms, particularly the leading edge and trailing edge. I adopted a 2kHz square wave as a favorite test. Some of the components are still below 20kHz and some are above. Ideally, a square wave at this frequency should be as good as a high quality square wave generator output. However, a poorly designed amplifier or an older amplifier that had tested good when it was new but now has deteriorated components may not meet the “good” amplifier criteria. Sensitivity to transients can be related to how we hear. However, the ear may behave more like a waveform analyzer such as an oscilloscope rather than a harmonic component analyzer.What do you know. He is making the same point intuitively that I made by quoting JJ on how our hearing works (in time domain not as a spectrum analyzer).
Warm up your highlighter, Amir! There may be pop quizzes on the material!
Can't wait.
For now, if you are right with your point of view in audio Steven, it shouldn't be this easy to use your own references and quote how they dispute your views. You are not even quoting anything from them! So confident you are that you just throw the titles at us hoping no one tries to see if they back your position?
The discussion here is about class D amplifiers. Contrary to popular myth, class D does not mean "Digital." The letter D was just the next one in the alphabet. So you working with mainframe computers gives you no familiarity whatsoever with the design of class D amplifiers.
That's all well known Amir and does not relate to the discussion. As usual Amir, you are just arguing with yourself.
Amir it would appear that with all of your usual attempts to distract the discussion from a critical question that you obviously don't want to respond to honestly which came about because you've posted a highly misleading article on your company web site. You've implicitly conceded your gross error about SMPS without taking responsibility for it. You appear to have no answer or correction to your egregiously bad false claims. You could at least quietly slink off and fix the web site, but that hasn't happened, either.
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Reinventing the Audio Power Amplifier: Mark Levinson No 53
By Amir Majidimeh
"While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. "
Amir, why don't you concede the point like an honest man or provide believable evidence that switchmode power supplies always makes amplifiers perform audibly worse which is your basic claim, above.
If you could provide reliable evidence that SMPS are as bad as you say with swichmode power amps, people around here who recommend and use them with switchmode power amps could be put back on the road to audio nirvana.
Mine certainly was not an 'out of context quote', my quotes were chosen more or less at random where my eye happened to land. Your quote is from a different sentence, not the same one I pulled mine from. And you failed to give page numbers for my 5 quotes.
10 demerits. Smileys and apples get you no credits.
Pop Quiz!:
Quote the entirety of the last question and answer.
the usual self-aggrandizing blather
The beauty part of providing you links to educational resource you've lacked, Amir, is that it provides them to others here, too, who are free to visit or revisit them at whim to put your incorrigible quote-mining into context.
We're onto you here, you know. This isn't your WTF forum, or even AVSF.
Horrors of horrors. Meyer agrees with the subjective reviewers as to which amplifier sounded better!
But until he starts doing proper DBT preference testing, his comments have no better intellectual support than theirs. It is all GIGO.
Same to you Ammar and the rest of the membership in US.
Thanks Amir. Hopefully we can make pardoning a turkey on Thanksgiving day a tradition.
Ok, where were we? Oh yes, you started a thread about amp distortion due to me posting that embarrassing subjectivist tripe (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html) about digital amp PS, filters, etc "sound" on your sales site.
Amir, as a no-Hobbyist who has repeatedly ad hominem attacked M&M, could you please post here in the "
Listening Tests" forum, what "listening test" method you used when "hearing" the:
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price.
What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was
ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.
cheers,
AJ
p.s., ignoring and evading answers....provide answers also.
If that doesn't upset folks here, this one for sure would:
(http://2eyespy.tripod.com/sitebuildercontent/sitebuilderpictures/home20th16.jpg)
Here is the caption for above:
Close up of Nordost SPM bi-wire speaker cable with WBT solderless locking banana plugs and the Legacy Whisper binding posts. The SPMs are in a protective custom semi-rigid vinyl/nylon mesh tubing.
Looks like he has not read those references on his web site.
Story of my life on this forum it seems.
Yes, story of your life if you mean intellectual dishonesty and zero reading comprehension.
Perhaps you can point out where he waxes about the "sound" of those wires when "listening", like a peddler would?
What if he simply likes how they look, while making zero claims about any audible benefit?
Is JJ a hypocrite for accepting those DVDA and SACDs as gifts, despite zero audible benefit vs his CDs? Nope. Only and intellectually bankrupt individual would claim so.
cheers,
AJ
Oh, btw, no pic
The beauty part of providing you links to educational resource you've lacked, Amir, is that it provides them to others here, too, who are free to visit or revisit them at whim to put your incorrigible quote-mining into context.
Steven, would you kindly indicate in that list which one of those papers/articles you have read?
We're onto you here, you know. This isn't your WTF forum, or even AVSF.
Ah, you smart ones .
The beauty part of providing you links to educational resource you've lacked, Amir, is that it provides them to others here, too, who are free to visit or revisit them at whim to put your incorrigible quote-mining into context.
Steven, would you kindly indicate in that list which one of those papers/articles you have read?
We're onto you here, you know. This isn't your WTF forum, or even AVSF.
Ah, you smart ones .
Right. Staying away from places where you have exceptional influence is IME a very good idea.
Horrors of horrors. Meyer agrees with the subjective reviewers as to which amplifier sounded better!
But until he starts doing proper DBT preference testing, his comments have no better intellectual support than theirs. It is all GIGO.
Garbage in, garbage out indeed. Yet Krab says your work is obscure and his is relevant information! He doesn't understand that preference can very much be subject to bias.
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.
cheers,
AJ
p.s., ignoring and evading answers....provide answers also.
amirm,
I don't have enough experience in amplifiers to really evaluate the arguments here, but the way you address everyone's posts in the most obnoxious, weirdly personal tone littered with creepy unneeded emotes really, really really makes it hard to consider the merits of your arguments. They are buried under so much foolishness one must really work to even realize they are there, and frankly, given the way they are presented I think few people will even bother. Which is a shame, you posted some good tests in the other thread suggesting that you are much more serious about this than your posts imply, but I fear the way you choose to express yourself will mean that no one will take you seriously.
Please consider how the way you conduct yourself will lead others to question your judgement and experience more carefully. A tiny bit of effort on your part might result in a much better reception.
Garbage in, garbage out indeed. Yet Krab says your work is obscure and his is relevant information! He doesn't understand that preference can very much be subject to bias.
(sigh)
Do your employees and clients have an inkling of truly *outstanding* amounts of time and verbiage you spend puffing up your own ego and waging your inane audio battles on the Internets?
At least spare a few of those many minutes to turn in your pop quiz answer, ok? The task was to quote the final question and answer in Meyer's article. Unlike this trivial baiting rubbish you've posted above, it's relevant to the topic here.
Great Holy Hand Grenade of Antioch, what IS this thread?
It's rather tall, I'd like a second one, now, about this high...
Great Holy Hand Grenade of Antioch, what IS this thread?
It is a good shrubbery.
Great Holy Hand Grenade of Antioch, what IS this thread?
It is a good shrubbery.
IT is?
... with a herring!
Great Holy Hand Grenade of Antioch, what IS this thread?
It's rather tall, I'd like a second one, now, about this high...
This thread is just getting warmed up, which is taking some time because of the bobbing and weaving by our esteemed guest from Madrona. ;-)
IMO the
real fun is over in the thread entitled "Audibility of Typical Digital Filters in a Hi-Fi Playback System, a follow-up to Meyer & Moran?"
The real fun part is where our esteemed guest pukes over Meyer and Moran for not following BS 1116, and then someone dredges up some publications he wrote and posted on his corporate site and asks the same question. Kryptonite!
There are rumors that Steve Balmer taught classes in dodging and bobbing when being asked tough questions over at MS... ;-)
Great Holy Hand Grenade of Antioch, what IS this thread?
It's collateral damage from the explosion of this thread (http://www.hydrogenaud.io/forums/index.php?showtopic=107124), discussing this paper: Audibility of Typical Digital Filters in a Hi-Fi Playback System (http://www.aes.org/e-lib/browse.cfm?elib=17497)
Amir has made claims about hearing both 16/44 HF filtering and Class D amp HF filtering (well, among other things also). I encouraged him (possibly the mods too) to make a separate thread to discuss these Class D amp "listening" tests of his, but he instead used it as an opportunity to create a generic "Amp distortion" thread, so that he could attack his old pal Arny. Rather than defend his claims about "hearing" Class D amps vs AB, etc, as he claimed here: Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Hard for me to tell when it's purely diversionary or masochism.
cheers,
AJ
Great Holy Hand Grenade of Antioch, what IS this thread?
It's rather tall, I'd like a second one, now, about this high...
Relentless stalking under the guise of scientific inquiry.
'Tis a silly thread.
Great Holy Hand Grenade of Antioch, what IS this thread?
It's rather tall, I'd like a second one, now, about this high...
Relentless stalking under the guise of scientific inquiry.
No inquiry. Never seen a bunch of doctors going to a forum where their patients hang out for scientific inquiry.
The thread is for all of you so please don't excuse yourself from the list Chu .
Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.
Before we go there, I have fully documented Arny and friend's tests here. Let's make sure you know how to respond to them before we talk about something else. I will answer on behalf of Arny the questions below and see what you do with them.
Please list your:
Set up, equipment, sound room noise levels, etc.
He explains the source (turntable), speakers and of course amplification. No mention of sound room noise levels. And no mention of "etc."
What AB and class D amps were compared?
He has compared two 200+ watt class AV amplifiers.
Who/how was the testing run while you "listened".
We don't know who was there when the three of them did the testing. We have to take their word that the results are as they are and they have "proven" that amplifiers sound different when tested on supposedly transparent performance (THD less than 1%).
What was the listener training?
I seem to recall Arny saying there was some training but none is indicated in the article.
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
No, it was not compliant with BS-1116.
Can you post the statistical results?
Sure. Here they are:
(http://amirviews.smugmug.com/photos/i-zfdGz3C/0/X3/i-zfdGz3C-X3.png)
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
They did not. They found the cheaper amp to be the better one even though a double blind ABX test is not revealing that way. That information must have come as a result of post-hoc analysis or the test was not really blind.
TIA.
cheers,
AJ
You are quite welcome Ammar. Would be great to see what you do with the type of information you seek. And satisfy Chu's desire for scientific inquiry.
amirm,
I don't have enough experience in amplifiers to really evaluate the arguments here, but the way you address everyone's posts in the most obnoxious, weirdly personal tone littered with creepy unneeded emotes really, really really makes it hard to consider the merits of your arguments. They are buried under so much foolishness one must really work to even realize they are there, and frankly, given the way they are presented I think few people will even bother. Which is a shame, you posted some good tests in the other thread suggesting that you are much more serious about this than your posts imply, but I fear the way you choose to express yourself will mean that no one will take you seriously.
Please consider how the way you conduct yourself will lead others to question your judgement and experience more carefully. A tiny bit of effort on your part might result in a much better reception.
I was going to start by thanking you for your advice but it did not work out so well for me last time. (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107604&view=findpost&p=882576)
Tom Hanks had a great line in the movie Forrest Gump:
"You know, it's funny what a young man recollects, 'cause I don't remember being born. I don't recall what I got for my first Christmas, and I don't know when I went on my first outdoor picnic, but I do remember the first time I heard the sweetest voice in the wide world."I don't remember most people I run into on forums who use aliases. But do remember yours because it is the same name as a beautiful (but dangerous) water way where I live called Saratoga Passage. This is the "sweet voice" I heard from you three years before I joined this forum:
amirm failed spectacularly at comprehending that example chart. That makes him at least clueless about codec testing, and probably stupid as well since its not really that hard to understand if you can use words and understand ideas. (my apologies if he simply does not speak good english and so could not read the chart properly) Hes arguing about codec testing. You know hes ignorant about codec testing. Why are you even having an argument with him?
Point out hes too ignorant to have useful ideas about this and move on.
This thread has 61 posts and 1541 views. So there are 25 views for every post. Something tells me there are good number of people who are reading and either find the thread useful or entertaining. I take either .
Respectfully,
Your Stupid Non-English Speaking New Member,
Amir
Edit: fixed the link. Now where is that English dictionary....
Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.
Before we go there, I have fully documented Arny and friend's tests here.
Fully documented? LOL. Amirs description of it is fully something - fully biased and fully BS. ;-)
One relatively important missing parameter is when the tests that Amir alleges he "Fully documented" took place. Of course he didn't mention that.
Carlstrom, David, Greenhill, Laurence, Krueger, Arnold, "Some Amplifiers Do Sound Different", The Audio Amateur, 3/82, p. 30, 31, also reprinted in Hi-Fi News & Record Review, Link House Magazines, United Kingdom, Dec 1982, p. 37.
The answer is, best that I can recall - 1981. The articles about it were published in 1982.
Questions like the one about BS1116 are pretty strange because BS1116 was originally published in 1994, over 20 years later. Yup, being less than fully omniscient we didn't comply with standards that weren't published the first time until over 20 years later.
http://www.itu.int/rec/R-REC-BS.1116/en (http://www.itu.int/rec/R-REC-BS.1116/en)
It's like faulting Henry Ford's first prototype car because of the styling of the fenders.
Would be great to see what you do with the type of information you seek.
We already know, since you have provided it.
The questions I asked are all rhetorical, because everyone can see your claims about amp testing, like being an objectivist, are a fraud.
But How Does it Sound, by Amir Majidimehr
OK, lots of technical BS talk to bedazzle the audiomoron, but does any of this impact the sound? You audiomorons may know that there are two schools of thought here. My strawman says all amplifiers more or less sound the same. While I say the exact opposite, with each sounding different like the smell of two different farts. I'll pretend not take a position in that food fight . But instead, speak of a much less controversial issue of pure power delivery.
As a subjectivist I'll prime you up with the trend of less of efficient speakers and somewhat limited power available from our wall sockets, the amplifier can run out of steam before your desire for dynamics does, at least in our minds. This usually translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, less than impactful bass and possibly a loss of pace and rhythm.
In some purely subjectivist comparison testing I have either done, or possibly just made up/fabricated, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price, that we happen to not sell. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant. I know this is the type of moronic rambling audiomorons like to hear, so I feed you.
If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a $50k pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive), not to mention make your wallet as empty as your head. We are happy to let you evaluate them with your own system to see the benefits of this technology. Seeing, hearing and peddling this amplifier was an eye-opener for me. I think it will be for you too.
cheers,
AJ
Mine certainly was not an 'out of context quote', my quotes were chosen more or less at random where my eye happened to land. Your quote is from a different sentence, not the same one I pulled mine from. And you failed to give page numbers for my 5 quotes.
10 demerits. Smileys and apples get you no credits.
Pop Quiz!:
Quote the entirety of the last question and answer.
Bzzzt! Time's up Amir. You failed *again*.
Here's the answer, from Meyer, 1991 'The Amp/Speaker Interface: Are Your Loudspeakers Turning Your Amplifier Into A Tone Control?':
Q: Then what does this say about other combinations of amplifiers and speakers? You got very different results for your three systems.
A: Most speakers are probably more like the one that produced the curves in Figure 3, but we need more tests like these to answer that question. What we've found so far suggests (1) that most good solid-state amplifiers probably sound identical, or at least very much alike, within their power limits; (2) that tube amplifiers (and solid-state amps designed deliberately to behave differently liek tube amps) will tend to behave differently with different speakers; and (3) that speakers with strongly varying impedance curves tend to make the two types of amplifiers sound different.
Now, that was written way back in the grunge era. It summarized the 'objectivist' line on amplifier difference...qualifications and all. Yet people like you have brayed since before and after that article, that 'we' say 'all amps sound the same' , period. And then you bring up something like Arny's article as a 'gotcha' to knock down your strawman. Do you see how ridiculous you look to someone who's actually aware of the literature associated with the "Great Debate"?
Here's a scan I made of my copy of the article. Now you have the *whole thing* Amir, instead of whatever snippets you found before. You can thank me later...on Teacher Appreciation Day.
https://dl.dropboxusercontent.com/u/2605734...erInterface.pdf (https://dl.dropboxusercontent.com/u/26057348/Meyer1991_AmpSpeakerInterface.pdf)
Would be great to see what you do with the type of information you seek.
We already know, since you have provided it.
The questions I asked are all rhetorical, because everyone can see your claims about amp testing, like being an objectivist, are a fraud.
Ah, I thought you had no technical/constructive reason. Now you know why I was not answering you .
As to the rest of your comment, I am 1000% comfortable with what is printed on my company's web site. Here is the article section where you got that amplifier write-up: http://www.madronadigital.com/Library/Library.html (http://www.madronadigital.com/Library/Library.html). Much of it is published outside of my company's web site.
Please allow me to turn the tables on you. This is the business end of your speaker at AXPONA 2014 high-end audio show:
(http://audiograb.files.wordpress.com/2014/05/ct6a6429.jpg)
What the heck kind of nonsense is that? You took a multi-thousand dollar flat ribbon speaker cable and shorted its outputs for one terminal and another one for the other binding?
What testing had you done that said your amp sounded better with your speakers that way? Breaking some new ground in the interface between amplifier and speaker Ammar?
This is the description of the gear from the blogger:
A rack full of ModWright Instruments gear was driving the VSFT-3, including a $5,250 KWA 100SE amp and $3,750 LS100 tube preamp. For sources, AJ had a Modwright modded Sony HAP-Z1ES and Oppo BDP-105. I didn’t get a chance to explore the HAP-Z1ES all that much, but I’m pretty sure that was driving the bus while I was in the room. The mods are pretty similar to what I have in my own Modwright-ed Oppo, but include an external PSU, a tube stage and a completely reworked output stage. $3k gets the mod on your own unit.
MG Audio Design cables were used throughout, including the giant flat ribbon Planus III speaker cables and the silver Planus AG1 interconnects.$5,250 amplifier? What testing led you to that selection Ammar?
I am 1000% comfortable with what is printed on my company's web site.
Great, lets start here
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
In comparison testing I have done...
switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
..translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.
You can either provide the testing methods for amp distortions you state you did above, or you're a consummate fabricator. Which was already established more than 5yrs ago (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16386041).
Originally Posted by amirm
I have said before that this method does not work for ABX testing. But I didn't perform an ABX test. The testing was AB.
In AB test, the bias substantially tilts toward the louder source. That was not the case here. The winning gear most likely had its level lower by 0.7db.
Also, keep in mind that while I talk about which side was "better," I was not making a fidelity/subjective statement. But rather, looking for specific distortion in DACs. This is different in normal blind tests where people are not told what is being tested and therefore, don't know what difference to look for. This is why I am not moved by how many people have flunked such tests. If they didn't know what material to use, and what to listen for, the results are not interesting.
The one liner that triggered this entire thread was my comment that you can approximate -- not match -- level matching by a two phase process where you increase levels of the losing side to see if it changes the outcome. If it does not, then you have something that perhaps rises to 70% confidence level.
Originally Posted by Terry Montlick
And you derive this probable number from exactly what statistical test??
Nothing that complicated. I give it one out of three chances to be wrong, based on more than a decade of conducting double-blind and subjective tests and formal evaluations of my hearing. In other words, I know what percentage of time I have made a fool of myself in such tests . Versus being right.
You didn't answer my question on how many blind tests you have been involved in.
Amir, given your long, sordid history of outright (test) fabrications, it makes sense you are satisfied with the similar ones on your sales store site.
cheers,
AJ
What testing had you done
This (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html) and this (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16385882).
What testing led you to that selection Ammar?
This (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html) and this (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16385882).
cheers,
AJ
p.s. you can't possibly know the amusement you're providing speculation those amp inputs are shorted.
I am 1000% comfortable with what is printed on my company's web site.
Great, lets start here
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
In comparison testing I have done...
switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
..translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.
OK, we started. Now what?
And tell us: do you have a competitive commercial interest that is harmed by the above quote from my article?
You can either provide the testing methods for amp distortions you state you did above, or you're a consummate fabricator.
I am a woodworker and now have a fantastic CNC machine. Last week I fabricated this panel for a client's theater:
(http://amirviews.smugmug.com/photos/i-mc6prvL/0/X2/i-mc6prvL-X2.jpg)
I don't wake up worrying what someone says online about what I have written. And just confirming, you have no electrical engineering degree or work experience constituting the same, yes?
Which was already established more than 5yrs ago
.
Statute of limitation is 3 years in this field Ammar.
Amir, given your long, sordid history of outright (test) fabrications, it makes sense you are satisfied with the similar ones on your sales store site.
I stand behind my work. Do you stand behind this one or do you prefer that it is hidden from view?
(http://audiograb.files.wordpress.com/2014/05/ct6a6429.jpg)
OK, we started. Now what?
Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.
p.s., ignoring and evading answers....provide answers also.
And tell us: do you have a competitive commercial interest that is harmed by the above quote from my article?
I'm neither shyster nor $cam peddler, so no.
I am a woodworker and now have a fantastic CNC machine. Last week I fabricated this panel
I doubt that's what you used to get those ABX logs. You certainly didn't mention it when you fabricated these test "results" (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16385882).
I stand behind my work.
Liar, or explain you amp audibility testing work here:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Lets see how the non-Hobbyist Amir performed
Listening Tests for Audibility of Audio Power Amplifier DistortionsOr tell us why you fabricated yet another subjectivist audiophile believer tale about ML amps you peddle for >$50k.
cheers,
AJ
And tell us: do you have a competitive commercial interest that is harmed by the above quote from my article?
I'm neither shyster nor $cam peddler, so no.
We will have to be the judge of the former Ammar. I am clarifying: you do not sell any audio equipment that uses class d technologoy with a switchmode power supply. Is that what you are saying "no" to?
Lets see how the non-Hobbyist Amir performed Listening Tests for Audibility of Audio Power Amplifier Distortions
Or tell us why you fabricated yet another subjectivist audiophile believer tale about ML amps you peddle for >$50k.
We will get to that. Just want to first establish the position of my counterpart.
Would you give us a headline of the last audio comparison test you did? Don't need all the details. Just what it was.
I opened this thread, saw that amir opened it and that the very first post sets up another straw man argument, I closed the thread. 'nuff seen.
We will have to be the judge of the former Ammar.
We are judging you based on your audibility claims and actions. Like this blatant fabrication 5yr ago (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16385882) and now this:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/Mark...3Amplifier.html)
In comparison testing I have done...
switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
..translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.
Your evasion provides the answers.
I am clarifying: I sell $50k $cam-amps that use class d technologoy with a switchmode power supply and have made numerous shyster claims about audibility in this amp audibility thread
Thanks for clarifying and yes, that's why we're here.
We will get to that.
You're going to admit it was all a fabrication like your +/- 10% DAC tests, or:
Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.
p.s., ignoring and evading answers....provide answers also.
cheers,
AJ
I opened this thread, saw that amir opened it and that the very first post sets up another straw man argument, I closed the thread. 'nuff seen.
(http://www.mtviggy.com/wp-content/gallery/trainwreck/featured.jpg)
Your evasion provides the answers.
[...]
p.s., ignoring and evading answers....provide answers also.
These can't both be true Ammar.
I will go ahead and answer the questions I asked you. You can correct me if I am wrong:
1. You do sell powered subwoofers that use class D amplification with switchmode power supply. Hence, my comment about potential performance problems is of concern for you.
2. The last audio comparison test that you did was sighted.
I will go ahead and answer the questions
Great, here you go:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Amir, regarding the Listening Tests of Audio Power Amplifier distortions you have done.Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was
ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.
cheers,
AJ
p.s. keep in mind, evading these amp audibility claims you made, only add to your previous fabrications and support of $cams
That didn't happen with AJ so we have to deal with him as appropriate.
You can start by dealing with the questions related to your amp distortion audibility claims (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html), the thread title.
That didn't happen with AJ so we have to deal with him as appropriate.
You can start by dealing with the questions related to your amp distortion audibility claims (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html), the thread title.
What happens if I don't Ammar?
I joins your large scrap heap of highly dubious subjectivist audiophile claims.
So much for discussing amp distortion audibility, particularly your Class D filtering claims.
That didn't happen with AJ so we have to deal with him as appropriate.
You can start by dealing with the questions related to your amp distortion audibility claims (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html), the thread title.
What happens if I don't Ammar?
I joins your large scrap heap of highly dubious subjectivist audiophile claims.
So much for discussing amp distortion audibility, particularly your Class D filtering claims.
I am good with that coming from you. Are we done or will you change your mind and re-post the same thing again?
That didn't happen with AJ so we have to deal with him as appropriate.
You can start by dealing with the questions related to your amp distortion audibility claims (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html), the thread title.
What happens if I don't Ammar?
I joins your large scrap heap of highly dubious subjectivist audiophile claims.
So much for discussing amp distortion audibility, particularly your Class D filtering claims.
I am good with that coming from you. Are we done or will you change your mind and re-post the same thing again?
Right, Amir wants a free pass to harshly criticize people for comments that are far more innocent than his own for-profit web site's egregious subjectivist propaganda.
So much for discussing amp distortion audibility, particularly your Class D filtering claims.
I am good with that coming from you. Are we done or will you change your mind and re-post the same thing again?
Am I done discussing listening tests for audibility of audio power amplifier distortions, in this
Audibility of Audio Power Amplifier Distortions thread, in the
Listening Tests forum, such as this one?
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound?, by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
No. Not done.
Why would we not discuss those
Listening Tests in this
Audibility of Audio Power Amplifier Distortions thread?
What is it about your listening tests that makes you so uncomfortable and unwilling to discuss them? You claim to have "heard" several differences, at LF and HF. Let's examine why.
cheers,
AJ
Am I done discussing listening tests for audibility of audio power amplifier distortions, in this Audibility of Audio Power Amplifier Distortions thread, in the Listening Tests forum, such as this one?
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound?, by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
No. Not done.
Why would we not discuss those Listening Tests in this Audibility of Audio Power Amplifier Distortions thread?
What is it about your listening tests that makes you so uncomfortable and unwilling to discuss them? You claim to have "heard" several differences, at LF and HF. Let's examine why.
Two words: Sighted evaluation.
While Amir mocks reason and personal integrity by picking nits in other people's DBTs, some done nearly 3 decades ago during the infancy of the art of bias-controlled listening tests of audio gear, he proudly flaunts the contemporary results of his sighted evaluations combined with egregiously flawed, yes even imaginary technical analysis on his for-profit corporate web site.
A great example of this was his stirring flame job on Brad Meyer, calling for his expulsion from the realms of professional audio, earlier in this thread.
"Watch what I say, not what I do!" seems to be his motto.
Two words: Sighted evaluation.
Possibly. He advocates for a rather unique "forget to remember" switching method listening test, described here (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method.html#post16216826), when he tested DACs back in 2001-02.
Originally Posted by amirm
The comparison I performed was using a Mark Levinson No360S against the on-board DACs in five to six DVD-A and SACD players, all playing the same time sync'ed CD. In other words, I would listen to the analog output of the player while its digital output would feed the ML DAC. All front panel lights were turned off in addition to video circuits (yes, all of that made a difference in fidelity).
The two sources were fed to the dual inputs of a Stax "earspeaker" electrostatic headphone amp. If you are not familiar with Stax, you can read learn more about them here: http://www.stax.co.jp/Export/ExportProducts.html (http://www.stax.co.jp/Export/ExportProducts.html). I have three of their units and results are consistent across the board although the highest end unit does make the job a bit easier. Using headphones allowed me to completely eliminate the room and take advantage of the amazing transparency of these headphones to listen for the slightest differences. To latter point, I would often listen to material at levels well above what I would use for listening to music, allowing me to hear detail that would otherwise be lost.
I then picked material that made it easier to detect differences between DACs. I am not going to disclose what constitutes such content. Without such material, the job can range from difficult to impossible. One has to know what could be damaged by a DAC and then use music that has such content. To give you an example, when you compress music, it is the transients that suffer. So something like guitar music is much more revealing than say, violin as the latter is much more harmonic than the sharp impulses of a guitar. Voices play the same role. None of these are useful for testing DACs though so don’t use that as a hint to the question posed . You can’t test the cornering of a car if you just drive it straight….
The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.
I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.
The results above were later objectively shown to be backed by some science in Stereophile magazine. In reviews of said players and Mark Levinson, it was shown that the former would only resolve to 14 or 15 bits of audio samples. Turning off the front panel pushed some up to 16 bits or so. The ML on the other hand, was tested to have equiv. of 19.5 bits. This is contrast to all the DACs being rated at "24 bits."
Now this testing is a few years old (probably circa 2001 to 2002). Maybe DACs have improved so much that the $20 part in the player is just as good as my then $8000 Mark Levinson DAC (which was hand tuned). If so, then I like to know who has tested the new ones and details of their methodology.
There you have it. Was it worth the wait?
Was this the method used for the ML vs other class D and AB amps, that Amir claims to have done listening tests (distortion) on?
Perhaps he can clarify in this amp distortion listening test thread he started.
cheers,
AJ
Am I done discussing listening tests for audibility of audio power amplifier distortions, in this Audibility of Audio Power Amplifier Distortions thread, in the Listening Tests forum, such as this one?
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
[...]
No. Not done.
Why would we not discuss those Listening Tests in this Audibility of Audio Power Amplifier Distortions thread?
What is it about your listening tests that makes you so uncomfortable and unwilling to discuss them? You claim to have "heard" several differences, at LF and HF. Let's examine why.
Good morning Ammar. I have been very clear that I am not at all uncomfortable with anything I have written or you have said about it. You can keep revisiting otherwise but my position is as I stated. You can't make me feel differently than I do.
As to the "unwilling to discuss" part, there is good reason for that. Please allow me to explain by rewinding the story.
During the past 6 months, a remarkable thing has happened. A number of double blind tests of high resolution audio vs CD spec were put forward and challenge made that no one can tell the difference. If anyone disagreed, they were told to show up with log files from foobar ABX plug in. Well, a number of us did exactly that. My results were posted on AVS Fourm and are summarized on WBF Forum here: http://www.whatsbestforum.com/showthread.p...ounds-different (http://www.whatsbestforum.com/showthread.php?15255-Conclusive-quot-Proof-quot-that-higher-resolution-audio-sounds-different) for those who have not seen them.
You guys in this forum were left out of these discussions until a month or so back. While the discussions on AVS and WBF forum were similar with detractors trying to find technical reasons for why the outcomes may not be correct, the vocal members here took a different approach. You simply dismissed the results by calling them lies, fabrication, etc. Here is one of many representative posts:
I've explained to you multiple times that I have no pecuniary interest in this matter and would not stoop to gaming/cheating on unsupervised Windows online games.
xnor made similar accusations saying I had a spectrum analyzer running (not sure how that explains the many other tests I passed where the spectrum was the same). Even Arny, who had never brought up people outright fabricating positive results, joined the crowd here saying since he has not observed these results, they can't be reliable.
Now, if this were a comment or two by you, I would think nothing of it. But the above tone and substance have dominated almost every post from the few of you. There is not one response to me that is not personal in nature such as what I am responding to now.
Let's pause for a moment and review the forum's Terms of Service #8:
8. All members that put forth a statement concerning subjective sound quality, must -- to the best of their ability -- provide objective support for their claims. Acceptable means of support are double blind listening tests (ABX or ABC/HR) demonstrating that the member can discern a difference perceptually, together with a test sample to allow others to reproduce their findings. Graphs, non-blind listening tests, waveform difference comparisons, and so on, are not acceptable means of providing support.I complied with all of this. The test clips were available for anyone to download and attempt to reproduce the results. And they were created by others. Testing was ABX and used foobar which is the favorite method in this forum. I even went as far as taking new tests in this forum with the latest version of Foobar ABX plug-in which has hashes for both the clips used and the log file itself. In other words, I went above and beyond what the forum considers "objective" results (an incorrect technical term by the way to refer to any listening test).
There is no requirement for independent supervision in TOS #8 and rightly so. This is not cancer drug trials. We are just discussing a hobby. If you don't like the results, move along.
Where would we be if independent verification was required? How many test results do you think you will get?
Back to this thread, you are demanding that I tell you more about my amplifier tests. You might think I am an idiot but I am not stupid . I put forward tests above that complied with every word and punctuation in the forum rules here. Yet it did not remotely get considered as useful data. Now you are asking me to put forward more test data on another topic? Why would you believe those results when you didn’t believe the ones already shared where every rule of the forum was followed?
Here is the most important part of my reply to you and a point I made on AVS Forum that the consequences of these discussions go way past these little borders. In our eagerness to deny the results of these tests, we have telegraphed to the world to not ever show up with any positive double blind test result to these forums. Because if you do, not only will your results be denied, but you yourself will be called every name in the book.
What motivation would anyone have from here on to run tests and share them here? It is not like folks were motivated to run these tests to being with. Now we have shown that even if they went through all the trouble and did everything perfectly, we are going to pull out our wild card: “you must have cheated!”
We need no objective data to say that. We just say it and say it over and over again. Get a few others to repeat the same and we think we have dismissed the data. Putting aside the craziness of that logic, what you have done is to demonstrate that you really didn’t need or want to see double blind test data. Asking for such a test was just a bluff, hoping the other side didn’t go through with it. But once they did, then we use the other tactic of accusing the other person being a cheater and that is that.
That is wrong Ammar. That is wrong Arny. That is wrong Steven (Krab). That is wrong xnor. That is wrong Saratoga. It is wrong, wrong, wrong. Did I say it is wrong? We need to be welcoming of the type of data we cherish: double blind test data. We need not panic that the world has come to an end because they dispute our notions of audio. Don’t post unprofessional remarks calling the person’s ethics into question. Because when you do, it all looks like a game and no search for science or intent of learning.
It takes incredible amount of time and energy to run these tests Ammar.
You must know that because I have yet to see you post the results of a single double blind test across countless threads on AVS and now here. Show some real interest in the data. Some kind member sent me a PM calling the few of you a "primitive mob.” And that I should not remotely assume that other members sanction the manner with which you interact with others who produce data that is not to your liking. Do you want to be known as a primitive mob Ammar? I assume not. So dial back the angst, anger and frustration. Put aside your emotions. It is not a healthy thing.
Now, I am not holding any hope that any of this will register with the few of you any more than it did when I brought up the same point on AVS Forum. But I am hoping that the others reading this, including the moderators, realize that we have done far more damage to our cause here than the data itself. We have shown that we are dogmatic, don’t value new data, are not unbiased and objective in how we look at other evidence. It is probably too later to right this ship but it is worth a try. The choice is yours. I won’t be here long term to matter. If the next obnoxious response comes and you stand idly by, then you have proven that this "objectivity" cause that we talk about is just a racket.
I will end by saying that I will share more information on my amplifier testing. But I will not do so on your terms Ammar.
One relatively important missing parameter is when the tests that Amir alleges he "Fully documented" took place. Of course he didn't mention that.
Carlstrom, David, Greenhill, Laurence, Krueger, Arnold, "Some Amplifiers Do Sound Different", The Audio Amateur, 3/82, p. 30, 31, also reprinted in Hi-Fi News & Record Review, Link House Magazines, United Kingdom, Dec 1982, p. 37.
The answer is, best that I can recall - 1981. The articles about it were published in 1982.
Questions like the one about BS1116 are pretty strange because BS1116 was originally published in 1994, over 20 years later. Yup, being less than fully omniscient we didn't comply with standards that weren't published the first time until over 20 years later.
http://www.itu.int/rec/R-REC-BS.1116/en (http://www.itu.int/rec/R-REC-BS.1116/en)
It's like faulting Henry Ford's first prototype car because of the styling of the fenders.
Hi Arny. The difference between 1994 and 1982 is 12 years, not 20 . Seriously, no disagreement on that at all. I had no expectation for you to follow the standard that you properly state did not exist then. AJ had a set of questions and compliance with that test was one of them so I simply said that you did not comply with it. I had no intention whatsoever to be critical on that point and apologize if it came across that way to you.
xnor made similar accusations saying I had a spectrum analyzer running (not sure how that explains the many other tests I passed where the spectrum was the same). Even Arny, who had never brought up people outright fabricating positive results, joined the crowd here saying since he has not observed these results, they can't be reliable.
Now, if this were a comment or two by you, I would think nothing of it. But the above tone and substance have dominated almost every post from the few of you. There is not one response to me that is not personal in nature such as what I am responding to now.
Let's pause for a moment and review the forum's Terms of Service #8:
8. All members that put forth a statement concerning subjective sound quality, must -- to the best of their ability -- provide objective support for their claims. Acceptable means of support are double blind listening tests (ABX or ABC/HR) demonstrating that the member can discern a difference perceptually, together with a test sample to allow others to reproduce their findings. Graphs, non-blind listening tests, waveform difference comparisons, and so on, are not acceptable means of providing support.
I complied with all of this.
Since it seems impossible for you to stay on topic and turning everything into train wrecks, trying to make others look as stupid as yourself in topics where they are not even involved, here are interesting links for all other readers (I doubt there are many given your #1 post straw man):
post about ToS (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107124&view=findpost&p=881982)
post about your intellectual dishonesty (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107124&view=findpost&p=882029) (based on 20+ pages of your typical amirm spiel)
you evading a simple 4 second test file since over a week ago (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107124&view=findpost&p=882145)
Considering all this, from your dishonesty to your inability to tell us what you hear in a 4 second test file, yeah, nobody can take anything you post seriously, especially not ABX logs.
Back to this thread
You should stay on topic in any thread on any forum, and not post
lies about what I or anyone else allegedly said in other threads/places. I know that doing that fits your personality perfectly, but it is considered very rude by "normal" people.
That's all I will post about your dishonesty here.
Since it seems impossible for you to stay on topic and turning everything into train wrecks....
Never mind about me xnor. Did you not post this yesterday?
I opened this thread, saw that amir opened it and that the very first post sets up another straw man argument, I closed the thread. 'nuff seen.
I guess you did not see 'nuff.
, trying to make others look as stupid as yourself in topics where they are not even involved, here are interesting links for all other readers (I doubt there are many given your #1 post straw man):
I am wondering. Why is this called a "straw man" and not "straw person?" Are we not being sexist here? Just wondering.
==========================
you evading a simple 4 second test file since over a week ago (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107124&view=findpost&p=882145)
Please allow me to remind you what transpired prior to your request:
Now, I gave you a method for you to discover the same. You asked me to PM you with test files to run. I mentioned an example here and you were flippant about it. Here it is again: http://www.hydrogenaud.io/forums/index.php?showtopic=68524 (http://www.hydrogenaud.io/forums/index.php?showtopic=68524). You see foobar logs there of people who say they have passed them. I put in my results in one of these two threads.
Run the test and report back the log file. We won't accuse you of doctoring them. Let's see if you can hear a difference. If you can, then you answer your own question. If you cannot then it answers my question that you are not a critical listener.
You claim to be able to hear steep filters at 21+ kHz. Okay, if I sent you some files could you identify such filters? (I, of course, wouldn't send you files that allowed you to cheat using a spectrum analyzer, for example.)
See above. Let's see how many more back and forths it takes for you to run a double blind ABX test. The very test we keep asking others to run. But somehow, we are gun shy about running it ourselves.
And please state if you think the others who passed David's test are cheating.
Considering all this, from your dishonesty to your inability to tell us what you hear in a 4 second test file, yeah, nobody can take anything you post seriously, especially not ABX logs.
I just decided what I want to Christmas: that you really not take me seriously.
Listen, this is just a hobby. Print your post and run it by a loved one and see what their reaction is. If you are afraid of doing that as I suspect, then you should realize that you have lost a sense of reality about the meaning of these discussions. I have not so I remain unmoved by your extreme emotional angst in your posts.
Two words: Sighted evaluation.
My answer is two words too: "Oh no!" Not that sin... Not that sin.
I asked AJ what type of listening test he last ran. He wouldn't answer but I guessed that it was "sighted evaluation."
In the parallel thread you post this in the last 24 hours:
I did some quick tests to see if one can easily tell the difference between no dither, RPDF dither and TPDF dither being applied to a conversion of a pure -60 dB sine wave from 32 bit floating point to 16 bit fixed point. The effects of no dither is clearly shown in the output 65 k point FFT analysis, but the difference between RPDF and TPDF is not clear at all to me...
Was that "quick test" a double blind ABX test? If so, where are the logs and the files so that we can reproduce what you heard? And were there any witnesses if I may ask?
It was not, right. Quick test means just that: you performed a sighted test and relied on your experience and judgment from falling into a ditch there.
It was OK for you and indeed countless others to runs sighted evaluations. This is routine in the industry. For every one blind test, we run hundreds of sighted tests. Could their outcome be wrong? Sure. But we have to get work done and by using expert listeners we accept sighted results. That is what engineering is all about. We have to produce products. We confirm our understanding once in a while in blind tests but that is not remotely the norm.
Earlier you mentioned that the motivation for the double blind test that I quoted in the first post was this:
We hooked the equipment up and started to listen to it. Greenhill provided us with a certain Eagles LP and instructed us to cue up a certain track and try to crank it up a little. We were rewarded with a fairly horrific crackle on certain bass notes. One of us said something like "That sounds ABX-able" and the test was on.
That was a sighted test, right? Was there sin attached to that? Why did you even need a blind test? Some differences like "horrific crackle" don't exist due to placebo or bias, do they? They don't. So clearly there is a class of test outcomes where experienced people can make judgements about that is useful for people who don't have access to the same gear and resources to run the same test.
When I write articles, I don't write them as a hobbyist who woke up one morning and ran some sighted cable tests. I know the theory and design of the systems with any listening test I perform. The sum total of my experience is what I am sharing.
As I promised Steven earlier, here are some additional quotes from the Meyer amplifier test.
One of the key requirements for a correct listening test is critical test signals/music tracks. We need content that is revealing of the differences we like to find. This is stipulated strongly in ITU BS1116 and is standard practice in research/industry. It is abundantly easy to use tracks that don't bring out the difference and proceed to declare there is no audible difference.
When a distortion is not uniformly apparent, finding the difference becomes a statistical effort. If I suck out 43 Hz out of the system, but you play content that has little in that frequency, then you won't hear the difference before and after I do that. I think we all agree that a system that has big hole at 43 Hz is broken. Yet we can trivially create results from double blind tests that say there is no problem at all. We may get lucky and throw music at the system that does have 43 Hz content, or the opposite. What are the odds?
Well, just like gambling, we like to improve our odds. We do that by using trained listeners who know what to listen for and find them easier than average listeners. And we help them further with critical music segments that makes the job easier and less subject to errors/nocebo, etc.
Let's put this knowledge to practice. Here are the results of the double blind tests that Meyer ran in his stereo review article:
(http://amirviews.smugmug.com/photos/i-b5RrMRg/0/X2/i-b5RrMRg-X2.png)
Look at the difference the type of signal makes. I have highlighted Pink Noise. See how that is revealing in all three test cases. Now look at the rest of the outcomes in test #2. All would be dismissed as not being good enough and equiv. declared in the two amplifiers.
The job of any amplifier is to be the proverbial "wire with gain." In other words it only amplifies but doesn't change anything. The moment one amplifier sounds different than another with pink noise, the game is over. It matters not that a million other pieces of music don't show it. It matters that we violated the "wire with gain" as that statement does not make an exclusion of a full spectrum signal like pink noise.
In this case we have objective proof that the pink noise data is correct. We know that the frequency response varied between the two amplifiers. So there was no need to throw music at the system. The job was done the moment pink noise showed revealing difference in amplifiers.
Unfortunately the audio test field is littered with people who throw random tracks of music at a system and proceed to declare equivalence. No attempt is made at determining what the potential problems are, and what kind of content best exercises it. This is my #1 beef with many listening tests. I hope the above data shows why.
I have been very clear that I am not at all uncomfortable with anything I have written or you have said about it.
Exactly why I stated: ignoring and evading answers....provide answers also.
You have made it clear to the world that you will evade answering any questions and humiliating yourself, about this:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound? by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Specifically these questions -
Please list your:
Set up, equipment, sound room noise levels, etc.
What AB and class D amps were compared?
Who/how was the testing run while you "listened".
What was the listener training?
Was
ITU-BS-1116 adhered to, as Amir the Pro/Industry Insider/Objectivist preaches, unlike the clumsy hobbyist M&M testing?
Can you post the statistical results?
Did you find any correlation between the harshness heard and price, or the fact that you purely coincidentally peddle the brand that "won" the audibilty test?
TIA.
As to the "unwilling to discuss" part, there is good reason for that.
Not if you did a valid amplifier comparison for audibility of distortion, the thread topic. Of course if you fabricated the whole thing like this (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html), then of course you do have reason to be "unwilling" to discuss your amp distortion test claims. I imagine that one still haunts you till this day...and now everyone here is aware of it and how you obtained "test results" of your own making.
Back to this thread, you are demanding that I tell you more about my amplifier tests.
Right. You claimed to
have done (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html) them and found all sorts of detectable distortion differences. Here, I'll remind you:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound? by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Now you are asking me to put forward more test data on another topic? Why would you believe those results when you didn’t believe the ones already shared where every rule of the forum was followed?
Not "another topic", but
this thread topic. Audibility of Audio Power Amplifier Distortions. Whether or not "I" believe the results, is irrelevant to whether the results are valid in nature...or not. You're not sharing your amp distortions test results with "me", but rather the forum/world. We understand your alarm.
That is wrong Ammar. That is wrong Arny. That is wrong Steven (Krab). That is wrong xnor. That is wrong Saratoga. It is wrong, wrong, wrong. Did I say it is wrong?
Ok Amir, we get you're the poor victim here, again...but the thread is about amp distortion tests. You claimed to have done some and got positives. This isn't an ABX log file you generate on a computer. So lets see the methods and results so others can attempt to repeat it.
It takes incredible amount of time and energy to run these tests Ammar.
And we thank you for already having done them here:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound? by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
So now lets see the methods and results, just like you did with Arnies tests, M&M, etc.
I will end by saying that I will share more information on my amplifier testing. But I will not do so on your terms Ammar.
That's ok, but this is a public forum, not my PM address. As long as this thread is about amp distortion test results, yours are and will continue to be fair game for discussion, evade all you want, as usual.
cheers,
AJ
Unfortunately the audio test field is littered with people who throw random tracks of music at a system and proceed to declare equivalence. No attempt is made at determining what the potential problems are, and what kind of content best exercises it. This is my #1 beef with many listening tests. I hope the above data shows why.
Then tell us how those potential problems were avoided and what tracks were used here :
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound? by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
That will help those trying to do these type of amplifier distortion tests, if that is actually your interest.
cheers,
AJ
As I promised Steven earlier, here are some additional quotes from the Meyer amplifier test.
You failed two pop quizzes, Amir. They were open book quizzes too, if you actually had the Meyer 1991 article.
And now you're
complaining that *in addition to* demonstrating nonmagical amp difference with pink noise, Meyer demonstrated it using musical signals too?
In text that you did not screen capture, Meyer himself of course describes the FR and the conditions under which the difference was audible *only* with pink noise - Figures/conditions 2 and 3. To everyone but you, it's naturally interesting to know whether differences apparent when using test signals would tend to manifest using normal listening fare...i.e., music. So yes, Meyer used both. Musical signals and pink noise both revealed amp differences in condition 1.
And you're criticizing him for that. Seriously, dude, WTF is your problem?
Here is the *point* of the article:
What we've found so far suggests (1) that most good solid-state amplifiers probably sound identical, or at least very much alike, within their power limits; (2) that tube amplifiers (and solid-state amps designed deliberately to behave differently like tube amps) will tend to behave differently with different speakers; and (3) that speakers with strongly varying impedance curves tend to make the two types of amplifiers sound different. -- Meyer 1991
No reasonable 'objectivist' can have a serious beef with statements as highly and properly qualified as those, but you have to find *something*, anything, to carp about....
NO ONE has to take Amir's word, or mine, for anything on this article. Anyone can download it now from here (https://dl.dropboxusercontent.com/u/26057348/Meyer1991_AmpSpeakerInterface.pdf)
As to the "unwilling to discuss" part, there is good reason for that. Please allow me to explain by rewinding the story.
During the past 6 months, a remarkable thing has happened. A number of double blind tests of high resolution audio vs CD spec were put forward and challenge made that no one can tell the difference. If anyone disagreed, they were told to show up with log files from foobar ABX plug in. Well, a number of us did exactly that. My results were posted on AVS Fourm and are summarized on WBF Forum here: http://www.whatsbestforum.com/showthread.p...ounds-different (http://www.whatsbestforum.com/showthread.php?15255-Conclusive-quot-Proof-quot-that-higher-resolution-audio-sounds-different) for those who have not seen them.
You guys in this forum were left out of these discussions until a month or so back. While the discussions on AVS and WBF forum were similar with detractors trying to find technical reasons for why the outcomes may not be correct, the vocal members here took a different approach. You simply dismissed the results by calling them lies, fabrication, etc.
it is true that several people demonstrated the ability to differentiate hi-res files from their downsampled offspring. For some it was fairly easy while for others more effort was required. However to call those who raised questions as detractors does not serve the interests of science. Questions of whether IM played a role are valid questions and one would, I hope, like to address the usual suspects as eliminating them serves only to place greater validity upon one's findings. Detractors or those who critically examine data have an important role in science. At one time for example, pictures of Mars' surface suggested a huge structure resembling a face. Proof that some beings constructed it that were not from this earth it was said. I think there was even a movie that used that premise. Yet when the same area was photographed with igher resolution, no more structure that resembled a face. Rather than poo poo such comments, it's better to embrace them.
Another matter is were the files cheatable. As Zillch has demonstrated for some there were slight level imbalances as well as time offsets. Could a person have inadvertently picked up on that and mistakenly attributed a difference to one or the other or both? Maybe. As part of the investigative process should that not be addressed?
Would a different means of resampling have created offspring more difficult to differentiate. There's an awful lot of SRC out there in the market and I'd imagine they're capable of doing different things. Could a person more skilled in the art created something more challenging or is everyone equally adept?
Stuart tested his listeners in the sweet spot but what happens when the spot isn't so sweet? Does 56% turn to 50%? And one of my favorites, the two beer test.
Amir, I have a tough time believing that you don't have a pretty good idea of the time stamps where you heard the differences and have not sought to articulate what you heard in the interests of full disclosure. This could lead to a fruitful path and a constructive discussion. Why keep it like a trade secret?
Amir, I have a tough time believing that you don't have a pretty good idea of the time stamps where you heard the differences and have not sought to articulate what you heard in the interests of full disclosure. This could lead to a fruitful path and a constructive discussion. Why keep it like a trade secret?
I guess science, for him, stops at 'something was heard'. No need to for anyone to know what, or why.
Amir, I have a tough time believing that you don't have a pretty good idea of the time stamps where you heard the differences and have not sought to articulate what you heard in the interests of full disclosure. This could lead to a fruitful path and a constructive discussion. Why keep it like a trade secret?
I guess science, for him, stops at 'something was heard'. No need to for anyone to know what, or why.
Initially I thought the reasoning was for others to work harder and by doing so hone their individual abilities plus that sense of personal accomplishment. The time has passed for coquettish behavior.
Two words: Sighted evaluation.
My answer is two words too: "Oh no!" Not that sin... Not that sin.
I asked AJ what type of listening test he last ran. He wouldn't answer but I guessed that it was "sighted evaluation."
In the parallel thread you post this in the last 24 hours:
I did some quick tests to see if one can easily tell the difference between no dither, RPDF dither and TPDF dither being applied to a conversion of a pure -60 dB sine wave from 32 bit floating point to 16 bit fixed point. The effects of no dither is clearly shown in the output 65 k point FFT analysis, but the difference between RPDF and TPDF is not clear at all to me...
Was that "quick test" a double blind ABX test?
No, it was an objective test (measurements). What is unlcear about "FFT"?
Amir I think that you are intentionally trying to test my patience by using an inherently irrational argument that I have already said that I did not tolerate from my subteen or teenaged children.
Since I'm staying with my children I even confirmed this yesterday with my oldest son. He said that he knew better to try such an irrational argument just based on knowing me even though he was a child at the time. He suggested that his younger brother who was shall we say more speculative in his behavior, probably tried it just once. We (my wife was present) laughed and agreed.
As any good parent knows, treating children rationally and holding them to rational standards is generally recognized as a best practice but I would add that showing a little emotion and irrationality is also good within bounds.
If so, where are the logs and the files so that we can reproduce what you heard? And were there any witnesses if I may ask?
It was not, right. Quick test means just that: you performed a sighted test and relied on your experience and judgment from falling into a ditch there.
I would suggest that the better informed participants in this forum could tell from the wording of the description of the test that it was an objective test. Why do I say that? Was it that the results of the test (and its sequel) were given in dB? ;-)
Amir, that fact that you obviously tell an objective test from a warm hole in the ground is not disingenous because your comments often fail from the standpoint of correct perception of relevant facts, and often represent a view of reality that is shaped by your personal agenda not logic or reason.
It was OK for you and indeed countless others to runs sighted evaluations.
I don't care if they run their tests while standing on their heads while spitting golden coins. ;-)
What is right is right and what is most efficient is most efficient.
This is routine in the industry.
Actually, if one is actually in the audio industry and/or a perceptive reader, one finds that the more professional, successful workers use objective tests where ever possible, if for no reason other than speed and convenience. They can still be faulted on the grounds of relevance, but their tests are often relevant.
I know of one or more highly successful designers of high quality and even high end speakers that base almost every engineering decision on objective measurements.
In the case of the tests I ran I never listened to anything. There are headphones in my kit but they are still packed up. The test segments ran 10 seconds and it would take 10 seconds to listen to each just once and just once rarely suffices. The FFTs took a second or two each, and provided results in a format that at least some here seem to have correctly perceived based on just the few words used to describe them.
For every one blind test, we run hundreds of sighted tests.
True for me as well, but while I listen a lot for the purpose of pleasure, I rarely
test anything by ear. I have at least 5 DVMs, and 5 more FFT-based audio test sets of various kinds, but I rarely if ever listen for any purpose than pleasure or content and I do a great deal of that. As well as I test technically, listening tests rarely reveal anything of use. My last effort was to set up a number of audio test sets that were compatible with my new laptop.
Could their outcome be wrong? Sure.
Both myself and my associates seem to work to a higher standard.
(part 2 follows - reply broken in half to circumvent conference software limitations on quotes per post)
But we have to get work done and by using expert listeners we accept sighted results.
Given that I've spent so much time in and out of audio R&D and based on my own work I feel free to dispute that.
That is what engineering is all about.
Perhaps as practiced in LDCs.
We have to produce products. We confirm our understanding once in a while in blind tests but that is not remotely the norm.
True but not for the stated reason. Relevant objective tests rule.
Earlier you mentioned that the motivation for the double blind test that I quoted in the first post was this:
We hooked the equipment up and started to listen to it. Greenhill provided us with a certain Eagles LP and instructed us to cue up a certain track and try to crank it up a little. We were rewarded with a fairly horrific crackle on certain bass notes. One of us said something like "That sounds ABX-able" and the test was on.
That was a sighted test, right?
Until the ABXing started
there was no test, just observation and speculation.
Why did you even need a blind test?
Asked and answered which is just another example of
hopelessly poor reading comprehension. When I converse with you Amir I know that the most clueless newbie reading my posts probably gets more out of them than you.
Some differences like "horrific crackle" don't exist due to placebo or bias, do they?
Asked and answered, and just another example of why I expect zero reading comprehension from you Amir and the facts like this bear me out.
They don't. So clearly there is a class of test outcomes where experienced people can make judgments about that is useful for people who don't have access to the same gear and resources to run the same test.
Whether you know it or not Amir the Levinson 53 article contains claims of audibility and technical claims that are controversial if not outright wrong. There is no evidence there to support the conclusions given. That is actually good because the claims are so wrong that support would violate the laws of physics.
Amir, most of the people on this forum write posts knowing that you will never admit to an error no matter how clearly spelled out and how well documented by independent sources of a high reputable nature.
When I write articles, I don't write them as a hobbyist who woke up one morning and ran some sighted cable tests.
Since every objective test result in the Levinson 53 article was credited to Stereophile, and there seems to be no evidence of DBTs, what other testing did you do Amir?
I know the theory and design of the systems with any listening test I perform. The sum total of my experience is what I am sharing.
As I have shown with 100s if not 1,000s of clear corrections to your gross errors, whatever you share Amir it is not exactly exemplary.
Amir, I have a tough time believing that you don't have a pretty good idea of the time stamps where you heard the differences and have not sought to articulate what you heard in the interests of full disclosure. This could lead to a fruitful path and a constructive discussion. Why keep it like a trade secret?
I guess science, for him, stops at 'something was heard'.
Where I live, that's not science at all. It is pure, unvarnished subjectivism
No need to for anyone to know what, or why.
Subjectivists often try to convince us what or why. Problem is, their explanations seem to be based on the laws of physics in some alternative universe. If that were true, I'm not sure that the alternastive universe would run very long, because even taken within themselves, the alternative science doesn't appear to be consistent with itself.
As I promised Steven earlier, here are some additional quotes from the Meyer amplifier test.
One of the key requirements for a correct listening test is critical test signals/music tracks. We need content that is revealing of the differences we like to find. This is stipulated strongly in ITU BS1116 and is standard practice in research/industry. It is abundantly easy to use tracks that don't bring out the difference and proceed to declare there is no audible difference.
When a distortion is not uniformly apparent, finding the difference becomes a statistical effort. If I suck out 43 Hz out of the system, but you play content that has little in that frequency, then you won't hear the difference before and after I do that. I think we all agree that a system that has big hole at 43 Hz is broken. Yet we can trivially create results from double blind tests that say there is no problem at all. We may get lucky and throw music at the system that does have 43 Hz content, or the opposite. What are the odds?
Well, just like gambling, we like to improve our odds. We do that by using trained listeners who know what to listen for and find them easier than average listeners. And we help them further with critical music segments that makes the job easier and less subject to errors/nocebo, etc.
Let's put this knowledge to practice. Here are the results of the double blind tests that Meyer ran in his stereo review article:
(http://amirviews.smugmug.com/photos/i-b5RrMRg/0/X2/i-b5RrMRg-X2.png)
Look at the difference the type of signal makes. I have highlighted Pink Noise. See how that is revealing in all three test cases. Now look at the rest of the outcomes in test #2. All would be dismissed as not being good enough and equiv. declared in the two amplifiers.
In this case we have objective proof that the pink noise data is correct. We know that the frequency response varied between the two amplifiers. So there was no need to throw music at the system. The job was done the moment pink noise showed revealing difference in amplifiers.
Depends on what one is trying to prove. The pink noise tests do, as you suggest provide reliable evidence that there was probably a frequency response difference.
However, is that enough?
Unfortunately the audio test field is littered with people who throw random tracks of music at a system and proceed to declare equivalence. No attempt is made at determining what the potential problems are, and what kind of content best exercises it. This is my #1 beef with many listening tests. I hope the above data shows why.
How do we know that the selections that Meyer used were not carefully chosen to be diagnostic where there are other kinds of audible differences to be heard?
Given that sighted evaluations are generally known to be highly prone to false positives, how do we know that they are using diagnostic content?
In your Levinson #53 amplifier test, what do we know about the musical selections that were used in the evaluation?
Since all listening tests of the #53 are per your own admission sighted, how do we know that your claims about it are based on anything but false positives?
See, here's the problem Amir. you seem to use tough standards with the people that you disagree with and in this case have insulted vigorously on this forum, and another far easier one for you and your other subjectivist buddies.
I my case I wrote up an experiment on HA that I believe most knowledgeable people would instantly know was based on objective tests, and you claimed vigorously and repeatedly that I used sighted evaluations. Needless to say your pistol seems to get half-cocked long before you determine there is even anything to aim at. ;-)
Whether you know it or not Amir the Levinson 53 article contains claims of audibility and technical claims that are controversial if not outright wrong. There is no evidence there to support the conclusions given. That is actually good because the claims are so wrong that support would violate the laws of physics.
Unless Amir ends his dancing evasion of his own
Listening Tests for
Audibility of Audio Power Amplifier Distortions, I see no point in answering a single diversionary question he asks about any other test, since these are all smokescreens for him to hide behind. I encourage all to steer him back to his own unanswered claimed tests.
If he is truly interested in
Listening Tests for
Audibility of Audio Power Amplifier Distortions, then his own purported tests, where he claims positive results, are all that are needed to demonstrate the validity of the thread topic.
Of course, if it's yet another complete farce like his DAC distortion "+/- 10% volume" listening tests I have linked numerous times, then he has ample reason to run form these amp distortion listening test claims of his.
He claims positives, not nulls for the thread topic. Let's see them....and how.
cheers,
AJ
Nothing is more sobering than to miss an audible difference in blind tests that can be shown to objectively be there and audible. Yes, I speak from embarrassing experience here .
Here is the best example of that in Meyer's test:
(http://amirviews.smugmug.com/photos/i-zwN3xJQ/0/X2/i-zwN3xJQ-X2.png)
The frequency response of a tube amp is compared to a transistor one. There is clear variation in response in the tube amplifier. Pink noise confirmed conclusively that it was audible. Yet, yet.... testing with the music selections did not reveal the difference!
Here are the scores again from the test #2:
(http://amirviews.smugmug.com/photos/i-b5RrMRg/0/XL/i-b5RrMRg-XL.png)
Pink noise garnered 99.9% confident result of difference between amps. In sharp contrast, combined music trials rendered only 34% confidence.
Had someone just presented the music trials at 34% confidence, we would all say that the two amps are equivalent. Yet that would be completely wrong conclusion.
This is why two things are critical in listening tests of this sort:
1. Was critical test content used that would bring out the differences. In this case the difference was frequency response variations and hence we needed content that would have content in the region of interest that would make it as easy as possible to detect the difference.
2. Were trained listeners used so that they could find the differences if not abundantly audible?
In this test with music, the issue could have been #1, #2 or both.
Lesson here is if the results of a listening test are negative, you need to establish that it is not due to #1 and #2. If you cannot, then the results are not reliable. This is why I am like a broken record when it comes to these two issues. If you don't know how to find the right material or have the critical listening abilities to hear non-obvious differences, then you have no business running such tests.
Edit:errrrrrr... typo as usual.
Are you trying to tell us that a negative result does not prove the null hypothesis? We already knew that!
Is there a reason you posted this pointlessly cantankerous 'spin' on Meyer's 1991 results *twice* now, Amir?
You aren't teaching anyone here anything with this. We know that type of probe signal matters. We know that training matters.
Meyer himself noted the difference between pink noise and music, and he himself does not claim these as be-all and end-all results. You conveniently neglect to post relevant text from the article.
e.g.
I did two sets of trials, one with a steady signal called pink noise that makes it easy to hear response differences and another with music.
Because of the relatively small number of trials in these tests, the results should be taken primarily as an indication of where to look and how to proceed with more thorough tests in the future.
Are you trying to tell us that a negative result does not prove the null hypothesis? We already knew that!
No. I am telling you exactly what I said: *how* to run such tests as to generate reliable results. The importance of revealing content. The importance of using trained listeners. And ignoring test data that doesn't do that.
If a test is not proper, you ignore it and don't look to it to have done anything for the null hypothesis one way or the other.
If you were looking to see if my gas tank is empty and hence the reason my car did not start, and proceeded to check the radiator instead, we don't get to make any judgement about what is wrong with my car. We throw out the tester's data as the person not being qualified to run such diagnosis.
I'm not sure what you mean by a "proper" test. Is a "proper" test one that gives the result that you wanted? And is an "improper" test one that gives results that you don't like?
I'm not sure what you mean by a "proper" test. Is a "proper" test one that gives the result that you wanted? And is an "improper" test one that gives results that you don't like?
Not at all. I thought I already explained what is proper and improper. A proper test has Proper content. And Proper listeners. Violated those two principals and I don't care what the outcome is. The results are unreliable.
Of course my views are shared by the international standards for finding small differences: ITU Recommendation Broadcast Standard 1116:
3.1 Expert listeners
It is important that data from listening tests assessing small impairments in audio systems should come exclusively from
subjects who have expertise in detecting these small impairments. The higher the quality reached by the systems to be
tested, the more important it is to have expert listeners.
6 Programme material
Only critical material is to be used in order to reveal differences among systems under test. Critical material is that which
stresses the systems under test.These are the first things you look for. If they are not there, the outcome whether you agree with it or not is not material.
Here is another insight from the test notes:
(http://amirviews.smugmug.com/photos/i-VP7kdQT/0/O/i-VP7kdQT.png)
Notice what great thing about pink noise: it keeps repeating so when you switch back and forth, you hear the "same" thing. Why is that important? It is because of how our hearing works.
The first part of our perception is a "tape recorder" that captures everything that is being delivered by the ear. Think of this as a lossless recorder. This is the short-term memory and highly reliable. Ever ask someone to repeat something only to remember exactly what they said? That is short term memory recall.
As you can imagine, the volume of such data can be huge. Estimates are in many megabytes in computer terms. There would be no way to keep recording and recording everything that comes in. To get around this problem, the short term memory has strict limits on it measured in seconds. Different research gives different numbers for this but it is "short few seconds" before the data is overwritten.
What happens next is smart filtering. The cognitive part of the brain kicks in to extract useful information. Was that your loved one talking? Female voice? Piano playing? Etc. This is your longer term memory and is based on characteristics extracted from the short term memory. Now you in kilobits order of magnitude so a lot can be saved and recalled.
When the differences are huge, like a male person talking instead of female, we can use our long term memory. But when differences get small where brain classification would ignore, then we must rely on short term memory.
Back to the test, the pink noise keeps repeating with the same characteristic. So we can switch and instantly hear the difference.
With music, that was not so in his testing. The music kept playing linearly. Going "back" to the previous source did not give you the same content as was just heard. This means that you must rely on the much less accurate longer term memory classification.
They tried to deploy a useful technique which is to pick something like a long note that lasts for a bit. This way when you switch inputs you are still hearing something similar. But similar is not the same as what was heard. When differences get small, you want to re-hear the exact same thing.
As such, it is critical to be able to give the user the ability to loop and re-hear the same segment as was just heard. From countless listening tests I have performed I can tell you with 100% confidence that the reliability of the test suffers and suffers big time when all that is provided is linear playback. I want to hear that one piano reverb trail that may be 1 or 1.5 seconds. I want to focus on that detail. I don't want to hear one note for one input and another note for the other input.
When we don't provide such tools to the listener, the last part of the quote comes true. It becomes very frustrating to perform the test. You think you heard something but when you try to go "back" to it, the music has already gone forward. So you have to re-listen and that quickly becomes tedious. And tiredness means more mistakes. Listeners start to vote randomly or just vote "A" which the latter explaining why we don't always land at 50-50 negative outcome.
Easy segment selection and looping is essential to finding small differences. Give me a good tool for that and the job becomes hugely simpler. You can see that in my double blind ABX test results. I am able to finish these tests with lightning speed when I have that ability. I give Foobar ABX plug-in pretty poor ratings in this regard by the way. Segment selection is painful due to poor user interface implementation. The new one unfortunately does not fix that and piles on more problems on top of that.
6 Programme material
Only critical material is to be used in order to reveal differences among systems under test. Critical material is that which
stresses the systems under test.[/color][/i]
Surely one needs to use some common sense here. The critical material must still be testing the thing that is to be determined. I could test how these amplifiers perform into an inductive load but then all I am testing is how they perform into an inductive load.
Until you can show me how testing with pink noise (which I never listen to) relates to listening to music (which I DO listen to) I am unconvinced.
Until you can show me how testing with pink noise (which I never listen to) relates to listening to music (which I DO listen to) I am unconvinced.
That's easily shown .
Here are the test results again. Please focus on test case #2:
(http://amirviews.smugmug.com/photos/i-b5RrMRg/0/X2/i-b5RrMRg-X2.png)
Would you say the results of those two tracks are more representative of the experience you have when you listen to your full collection of music? I.e. you won't reliably hear any coloration?
What you have shown is that in at least one case the pink noise test does not correlate to testing with music.
What you have shown is that in at least one case the pink noise test does not correlate to testing with music.
No. The data shows that the two music clips, just those two, don't correlate with the results of the pink noise.
The pink noise however, 100% correlated with objective differences that we know create coloration. It told the truth. The two music samples did not.
There are some 10,000,000 commercial music tracks. We would be lucky to perform a listening test with just 10 of them. How would we claim that those 10 clips represent 10 million tracks people may listen to? We can't, right?
Now, you are right that the pink noise is unlikely to be one of those 10 million tracks . However, to the extent it is the most difficult track and we use that to find a transparent system, then we have very, very high assurance that across those 10,000,000 tracks (and millions of listeners) we have a transparent system.
Now, if no system can pass the test then sure, we have picked too difficult of a test signal. But to the extent we can find transparent gear, then the clip is very appropriate to use for testing. And what we must do if we want to represent equality between systems from negative outcomes.
Now, if no system can pass the test then sure, we have picked too difficult of a test signal.
What test signal did you use here to get these positives?
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound?, by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Pink noise?
Is there a reason you posted this pointlessly cantankerous 'spin' on Meyer's 1991 results *twice* now, Amir?
Yes, to avoid answering anything about this
Audibility of Audio Power Amplifier Distortions Listening Test he claims to have done: http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
No test material listed....or anything, yet claiming positives and some other ridiculous nonsense about Class D vs AB power supplies and "bass".
Btw, your Inbox is full.
cheers,
AJ
What you have shown is that in at least one case the pink noise test does not correlate to testing with music.
No. The data shows that the two music clips, just those two, don't correlate with the results of the pink noise.
The pink noise however, 100% correlated with objective differences that we know create coloration. It told the truth. The two music samples did not.
Amir, if you were more honest you'd note that Meyer himself wrote that when he used speakers that did not present a difficult load for the amps, the small measured FR differences was "
faintly audible with pink noise" and not at all to him, with music. He ascribed the differences to the 0.25dB difference in the 'vocal' range to which we are very sensitive (300-500Hz).
A 0.25dB difference,
faintly audible to him, only when pink noise is used. And even in the more robust case where both pink noise *and* music revealed a difference, it was only when the systems were not biamped. Many more systems today *are*, of course, biamped, than they were back in 1991....thanks to the popularity of active subwoofers
So I'd say that your 'truth' here is, at best, a
piddling one. Under most conditions -- listening to music via non pathological speaker/amp combos -- the difference is *in practice* likely to be
inaudible, as it was even between this tube amp and this SS amp under 2 out of 3 conditions. THAT is the important truth.
Since the start of the "Great Debate", hi end amps have been promised to routinely yield big, obvious difference for the music lover. Neil Young and the hi rez cheerleading squad promises that 'high resolution' audio will do the same.
In fact, neither of them do.
Readers, you need not take Amir's quote-mining (or my responses) of the Meyer 1991 Stereo Review article as gospel. You can read it for yourself:
https://dl.dropboxusercontent.com/u/2605734...erInterface.pdf (https://dl.dropboxusercontent.com/u/26057348/Meyer1991_AmpSpeakerInterface.pdf)
I am not a girl. It was blue noise.
Or imaginary noises in your head that sounded "harsh" and "bassy". Since there is zero evidence showing any test actually took place.
You said it AJ.
No Amir, that's
your name on this subjectivist audiophile tale, see:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
But How Does it Sound?, by Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
That's
you making multiple absurd claims about Audibility of Audio Power Amplifier Distortions Listening Tests. Now you hide from it. Nothing about listener training, program material, level matching (+/- 10% ??), etc, etc.....while demanding info about every one of those, in other tests. Pot, meet kettle.
For you it always is....
That's ok Amir. I'll continue to ask about
your claimed amplifier listening tests, in the Audibility of Audio Power Amplifier Distortions thread, out here in the open for all to see.
We appreciate you starting a thread, on a topic that you claim to have done tests of, yourself.
Literally.
cheers,
AJ
So I'd say that your 'truth' here is, at best, a piddling one. Under most conditions -- listening to music via non pathological speaker/amp combos -- the difference is *in practice* likely to be inaudible, as it was even between this tube amp and this SS amp under 2 out of 3 conditions. THAT is the important truth.
No, there is no such "truth" in the article. You are giving us your opinion devoid of what is said there. This is what is in the article, word for word:
(http://amirviews.smugmug.com/photos/i-QgxjBm8/0/X3/i-QgxjBm8-X3.png)
It says it sounded better. It says it added warmth that was pleasing with most material. It says it softened upper midrange hardness. It said it gave vocals more natural sound. These are benefits/characteristics that audiophiles cherish. Have you not ever listened to a tube amplifier Steven?
How can you twist this into "in practice likely to be inaudible." You have to be kidding us.
Since the start of the "Great Debate", hi end amps have been promised to routinely yield big, obvious difference for the music lover.
And the above direct quote from Meyer absolutely confirms that. Well designed tube amps absolutely sound delicious and nice. I have no use for them because I like power and don't care for their maintenance. But don't take the position that they don't have better subjective sound. Your own reference says they do in no uncertain terms.
Whatever sound tube amps have or impart depends upon the impedance profile of both the amp and the speaker. The impdedance profile of the tube amp as well as the distortion isn't constant as power goes up. Throw in the different favors of tube amps like SET and OTL along with different taps and it may well add warmth or make things sound boomy or just act like a SS amp. I agree with the maintenance part but they sure can be works of art.
I am good with that coming from you. Are we done or will you change your mind and re-post the same thing again?
If we are going to impose a moratorium on 'posting the same thing again', please let's not be selective in applying it, OK?
So I'd say that your 'truth' here is, at best, a piddling one. Under most conditions -- listening to music via non pathological speaker/amp combos -- the difference is *in practice* likely to be inaudible, as it was even between this tube amp and this SS amp under 2 out of 3 conditions. THAT is the important truth.
No, there is no such "truth" in the article. You are giving us your opinion devoid of what is said there. This is what is in the article, word for word:
(http://amirviews.smugmug.com/photos/i-QgxjBm8/0/X3/i-QgxjBm8-X3.png)
It says it sounded better. It says it added warmth that was pleasing with most material. It says it softened upper midrange hardness. It said it gave vocals more natural sound. These are benefits/characteristics that audiophiles cherish. Have you not ever listened to a tube amplifier Steven?
How can you twist this into "in practice likely to be inaudible." You have to be kidding us.
Hmm, does 'under most conditions', to you, include tube amps driving the top part of biamped systems ? Is that a vastly popular choice these days?
Meyer himself noted in his conclusion, which I have already quoted in full here (and which you failed a pop quiz on already) , that tube amps -- and SS amps designed to sound like tube amps -- are likely to 'behave differently' from SS amps. Whoop de do! There's your niche market, Amir, go for it.
Since the start of the "Great Debate", hi end amps have been promised to routinely yield big, obvious difference for the music lover.
And the above direct quote from Meyer absolutely confirms that. Well designed tube amps absolutely sound delicious and nice. I have no use for them because I like power and don't care for their maintenance. But don't take the position that they don't have better subjective sound. Your own reference says they do in no uncertain terms.
..
Whatever sound tube amps have or impart depends upon the impedance profile of both the amp and the speaker. The impdedance profile of the tube amp as well as the distortion isn't constant as power goes up. Throw in the different favors of tube amps like SET and OTL along with different taps and it may well add warmth or make things sound boomy or just act like a SS amp. I agree with the maintenance part but they sure can be works of art.
That warm tubey goodness (which I have heard) only was audible with music when the system was biamped. And only when he used speakers that were a tough load. You left that part out. IOW, you have to 'match' your tube amp to the 'right' system to get that sound*. Meyer talks about this too, in another part you didn't quote.
*I'd call that 'pathological' audio behaviour, but YMMV.
That warm tubey goodness (which I have heard) only was audible with music when the system was biamped. And only when he used speakers that were a tough load. You left that part out. IOW, you have to 'match' your tube amp to the 'right' system to get that sound*. Meyer talks about this too, in another part you didn't quote.
No, I didn't leave anything out. I provided an exact cut out of the article with the complete answer. Here is the concluding paragraph for the whole article:
(http://amirviews.smugmug.com/photos/i-n3vhLWb/0/X2/i-n3vhLWb-X2.png)
For solid-state amps he is providing his opinion that the likely sound the same but no back up is provided in the article. He also adds an undefined catch: within their power capability. As a user, you have no idea when that limit has been hit. Dynamic power limiting will cause coloration which can last just milliseconds.
For tube amplifiers, he is saying you basically need to expect different sound with different speakers without any of the qualifications you are trying to say on his behalf.
The conclusions as he states them is quite different than our marching orders in forums. Have someone say they replaced an AVR with a monoblock and heard a difference and hell will break lose. The person will be told that is an impossibility. Yet, above is your expert witness saying that could happen.
And this is what he says above that concluding remark:
(http://amirviews.smugmug.com/photos/i-nPjcpTp/0/O/i-nPjcpTp.png)
This torpedos any statement that amplifiers sound the same. That even if two amps have been shown to sound the same in blind tests, all you have to do is change the speaker and the sound will be different.
Audiophiles we hate talk about this all the time. They call it "synergy." Here is your expert witness saying that is 100% true.
(http://i216.photobucket.com/albums/cc73/AJinFLA/MadronaML53amp.jpg)
For solid-state amps he is providing his opinion that the likely sound the same but no back up is provided in the article.
Amir, you say almost the exact same thing in yours, 3rd sentence, but no back up is provided in the article. Very sloppy.
He also adds an undefined catch: within their power capability.
Amir, I've highlighted where you make similar claims about amplifier power limits, but provide zero data for these purely subjectivist claims. Highly unprofessional, hobbyist at best.
The conclusions as he states them is quite different than our marching orders in forums. Have someone say they replaced an AVR with a monoblock and heard a difference and hell will break lose.
Amir, the conclusions you state about Class D HF harshness, super bass and various amp "sounds", are exactly the same as on subjectivist audiophile hive forums. Have a rational person say lets see some supporting honesty controls testing evidence and all hell will break loose. Not terribly objective at all.
cheers,
AJ
Amir, the conclusions you state about Class D HF harshness, super bass and various amp "sounds", are exactly the same as on subjectivist audiophile hive forums.
Don't know subjectivist audiophile forum members writing things like this: http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
The so called “interleaving” method has a great advantage over traditional class D designs as the interleaving factor acts as a multiplier on the switching frequency. As an example an 8-way interleaved output stage run at 500 KHz, acts the same as a class D amplifier running at 4 MHz! This makes filter design much simpler as we have plenty of time to go from conducting the full audio response, say up to 50 KHz, to full reject of the 4 MHz effective signal. Indeed that is how the Mark Levinson No 53 works. Here is a comparison of the distortion prior to filtering for the traditional 2-way interleaving to 8-way method used in Mark Levinson No 53:
[...]
Being a “statement” product, the Mark Levinson No 53 sports a traditional linear power supply from the Mark Levinson Reference 532 amplifier. The temptation in class D designs is to use a switching mechanism in the power supply itself feeding the amplifier. While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. Copious amount of “negative feedback” can be used to compensate for this but that leads potentially to amplifier instability (and some would claim compromised audio fidelity). Are you able to follow this kind of technical explanation Ammar?
Have a rational person say lets see some supporting honesty controls testing evidence and all hell will break loose. Not terribly objective at all.
Last time you and I talked about objectivity and double blind tests, you had an awful time admitting that you don't believe in it. Has anything changed?
-----
Quote:Originally Posted by
AJinFLA At least I'm honest about not blind testing my loudspeakers...
This is what it took for Ammar to be "honest:"
Quote:Originally Posted by
amirmWe would only know that [form follows function of his speakers] if you had run a blind test against some other ones, now wouldn't we?
Quote:Originally Posted by
AJinFLA A blind test of "Form following function"???(http://www.avsforum.com/avs-vb/images/smilies/confused.gif)
Quote:Originally Posted by
amirm No need to be confused. You want me to listen to your speakers. I am asking what type of blind listening tests you have run on it. You do believe in blind testing of speakers, do you not?
Quote:Originally Posted by
AJinFLATo verify what claim? "Form follows function"???(http://www.avsforum.com/avs-vb/images/smilies/confused.gif) HDMI audib....?..ooops, sorry (http://www.avsforum.com/avs-vb/images/smilies/tongue.gif).
Quote:Originally Posted by
amirmYou do believe in blind testing of speakers, do you not?
Quote:Originally Posted by
AJinFLASure do. And measuring audible difference sound waves.
Quote:Originally Posted by
amirmAJ, I can't follow your answer. Have you run any blind tests of your speakers against others to verify it performs better?
Quote:Originally Posted by
AJinFLAPerhaps you could have JJ..or someone high school, or anyone who isn't an audiophile...explain it, slowly, to you?
Performs better than....what?
Where did I make such a claim, that it performed better than X?
Quote:Originally Posted by
amirmSo you designed a speaker with no goal for it to be better than anything? And think I should come and listen to it and be impressed with that goal in mind?
Quote:Originally Posted by
AJinFLAI designed it to be better than the last, at meeting known, scientifically established thresholds, such as smoothness of FR on and off axis, etc, etc.
Quote:Originally Posted by
AJinFLAI said
blind tests for already established audibility thresholds (such as FR JNDs) are unnecessary, not what you just fabricated above.
============
"Blind tests are not necessary...AJ in Florida"
Don't know subjectivist audiophile forum members writing things like this:
But How Does it Sound by Amir Majidimehr
OK, lots of technical talk but does any of this impact the sound?
You may know that there are two schools of thought here. One that says all amplifiers more or less sound the same.
Actually, that's
exactly what they write. First, some BS about amp "sound", immediately followed up by a strawman. Perfect, yes.
Here's more:
This usually translates into the amplifier sound becoming leaner at higher volumes, together with increased high frequency distortion, and less than impactful bass.
Notice how those subjectivist audiophile forum members posit their purely subjective perceptions as facts, with zero supporting evidence. No blind tests or anything about methods, setup, training, etc, etc.
Just purely subjectivist blathering.
More:
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
Are you able to follow this kind of technical explanation Ammar?
No, there is nothing "technical" to follow, just a bunch of subjectivist audiophile forum member tripe about "incredible low frequency control and power". What the heck does that mean? "They beat out linear class AB amplifiers almost regardless of price." Really? Talk about BS hyperbole. Where are the objective listening tests/data supporting such a preposterous claim? Nowhere, zero data, no blind tests or anything about methods, setup, training, material selection, pink noise?, music? etc, etc.
Last time you and I talked about objectivity and double blind tests, you had an awful time admitting that you don't believe in it. Has anything changed?
If you are referring to this (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html) or this:
If what I present doesn't meet some high bar, so be it....
The comparison I performed was using a Mark Levinson No360S against the on-board DACs in five to six DVD-A and SACD players, all playing the same time sync'ed CD. In other words, I would listen to the analog output of the player while its digital output would feed the ML DAC. All front panel lights were turned off in addition to video circuits (yes, all of that made a difference in fidelity).
The two sources were fed to the dual inputs of a Stax "earspeaker" electrostatic headphone amp. If you are not familiar with Stax, you can read learn more about them here: http://www.stax.co.jp/Export/ExportProducts.html (http://www.stax.co.jp/Export/ExportProducts.html). I have three of their units and results are consistent across the board although the highest end unit does make the job a bit easier. Using headphones allowed me to completely eliminate the room and take advantage of the amazing transparency of these headphones to listen for the slightest differences. To latter point, I would often listen to material at levels well above what I would use for listening to music, allowing me to hear detail that would otherwise be lost.
I then picked material that made it easier to detect differences between DACs. I am not going to disclose what constitutes such content. Without such material, the job can range from difficult to impossible. One has to know what could be damaged by a DAC and then use music that has such content. To give you an example, when you compress music, it is the transients that suffer. So something like guitar music is much more revealing than say, violin as the latter is much more harmonic than the sharp impulses of a guitar. Voices play the same role. None of these are useful for testing DACs though so don’t use that as a hint to the question posed . You can’t test the cornering of a car if you just drive it straight….
The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.
I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.
The results above were later objectively shown to be backed by some science in Stereophile magazine.
....Then yes, I don't believe your tests are either objective or blind, much less double. They reek of purely subjectivist tripe, so no, nothing has changed in at least 12 years (assuming the DAC distortion listening "test" was '02).
I bet they go well with subjectivist audiophile forum members on AA, WTF??, etc forums. They love that amp "sound" DAC "sound" stuff. Slurp it right up. Good "business understanding" I suppose.
cheers,
AJ
That warm tubey goodness (which I have heard) only was audible with music when the system was biamped. And only when he used speakers that were a tough load. You left that part out. IOW, you have to 'match' your tube amp to the 'right' system to get that sound*. Meyer talks about this too, in another part you didn't quote.
No, I didn't leave anything out. I provided an exact cut out of the article with the complete answer. Here is the concluding paragraph for the whole article:
Now AMir, you know and I know know and everyone who can see knows that this is nto the screencap you posted before
(http://amirviews.smugmug.com/photos/i-n3vhLWb/0/X2/i-n3vhLWb-X2.png)
Tsk, tsk Amir, you know and I know and everyone who has followed along knows that this is
not the section you quoted in teh post I was replying to, which did
not have the 'complete answer' (and which now, oh dear, lives in the cornfield (http://www.hydrogenaud.io/forums/index.php?showtopic=107643&view=findpost&p=883123) )
This screencap you've got here is a section *I*
already posted -- the final q/a of the article. I asked
you to post it as your second pop quiz,
days ago, and you
failed. Posting it *now* is far too late to amend your failing grade, alas.
Worse, this is *not* the section I was referring to up there (I've now bolded it), where Meyer talks about having to 'match' amp to speaker, to get that warm tubey goodness. That spans a few Q/As, including an interesting digression on philosophy of hardware design.
Might be on your next pop quiz. Better read up on it.
The conclusions as he states them is quite different than our marching orders in forums. Have someone say they replaced an AVR with a monoblock and heard a difference and hell will break lose. The person will be told that is an impossibility. Yet, above is your expert witness saying that could happen.
An SS amp and a tube amp sounding different would *hardly (http://www.hydrogenaud.io/forums/index.php?showtopic=107277&view=findpost&p=880540)* be deemed impossible (http://www.hydrogenaud.io/forums/index.php?showtopic=18&view=findpost&p=170)here, Amir*. You simply don't know what you're talking about re: Hydrogenaudio. But you're getting an *excellent* education.
(*I've linked to the newest and oldest refs to tube amps I can find here)
And this is what he says above that concluding remark:
(http://amirviews.smugmug.com/photos/i-nPjcpTp/0/O/i-nPjcpTp.png)
This torpedos any statement that amplifiers sound the same. That even if two amps have been shown to sound the same in blind tests, all you have to do is change the speaker and the sound will be different.
Audiophiles we hate talk about this all the time. They call it "synergy." Here is your expert witness saying that is 100% true.
tsk, tsk, Amir, another line taken out of context. You're incorrigible. In context of what's written *before and after*, that one-line answer makes a lot of sense. Cherry-picking is a form of cheating.
That answer isn't meant to stand all by itself -- it comes after pages of explanation where the 'questioner' has been carefully led to a place of understanding. And it precedes the coup de grace that lays out , carefully qualified, conditions where audible difference likely does and does not manifest in amps.
And it's simply ludicrous to claim it 'torpedoes
any statement that amps sound the same'. In the case where two SS amps under comparison aren't being driven to distortion/stressed by speakers with 'strongly varying impedance curves',Meyer would say, quite correctly and confidently, that they will probably sound the same, with music, in a blind test. That's torpedo-proof.
And the beauty part is: it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (
the only situation here where *music* acted as a revealing probe signal)
Might be on your next pop quiz. Better read up on it.
Since you liked my last quote , here is another from Mr. Meyer's article:
.
But alas, Dancing Man from Madrona, it does not support the audiophile nostrum that *all amps sound different". Which is really at the core of hi-end belief systems, like the more recent 'high rez lifts the veil of Redbook'.
You know, the beliefs you peddle.
Might be on your next pop quiz. Better read up on it.
Since you liked my last quote , here is another from Mr. Meyer's article:
.
There is no greater pride in China than for a parent to say their 9 year old son made that.
And this is what he says above that concluding remark:
(http://amirviews.smugmug.com/photos/i-nPjcpTp/0/O/i-nPjcpTp.png)
This torpedos any statement that amplifiers sound the same. That even if two amps have been shown to sound the same in blind tests, all you have to do is change the speaker and the sound will be different.
Audiophiles we hate talk about this all the time. They call it "synergy." Here is your expert witness saying that is 100% true.
Amir, since you claim such extensive audio professional expertise, please just tell us an quick anecdote about the blind tests of amplifiers that you have personally performed.
Being a “statement” product, the Mark Levinson No 53 sports a traditional linear power supply from the Mark Levinson Reference 532 amplifier. The temptation in class D designs is to use a switching mechanism in the power supply itself feeding the amplifier. While this provides improved efficiency it aggravates a weakness of switching amplifiers which is their very high sensitivity (compared to linear amplifiers) to power supply voltage variations and noise which unfortunately get worse with switching supplies. Copious amount of “negative feedback” can be used to compensate for this but that leads potentially to amplifier instability (and some would claim compromised audio fidelity). [/i][/color]
Are you able to follow this kind of technical explanation...?
I've shown several times here how the paragraph above is hopelessly flawed, and nothing that Levinson, Crown or any division of Harman would publish on their own.
Interestingly enough, you have not seen fit to reply to my comments in any meaningful way. You did try to turn the discussion personal by making some disparaging comments about PC power supplies, but I was able to easily debunk their hopelessly flawed technical content, and again you ran away from the discussion.
tsk, tsk, Amir, another line taken out of context. You're incorrigible. In context of what's written *before and after*, that one-line answer makes a lot of sense. Cherry-picking is a form of cheating.
That answer isn't meant to stand all by itself -- it comes after pages of explanation where the 'questioner' has been carefully led to a place of understanding. And it precedes the coup de grace that lays out , carefully qualified, conditions where audible difference likely does and does not manifest in amps.
And it's simply ludicrous to claim it 'torpedoes any statement that amps sound the same'. In the case where two SS amps under comparison aren't being driven to distortion/stressed by speakers with 'strongly varying impedance curves',Meyer would say, quite correctly and confidently, that they will probably sound the same, with music, in a blind test. That's torpedo-proof.
The problem is Steven, our esteemed member Arny, has proven that high-power solid state amps sound different:
(http://amirviews.smugmug.com/photos/i-nTpXsqF/0/L/i-nTpXsqF-L.png)
And the beauty part is: it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (the only situation here where *music* acted as a revealing probe signal)
"music" did not act as revealing probe signal. A couple of tracks picked at random by a tester does not constitute a proper test.
If two amplifiers sound different on pink noise, they are different sounding. Period. End of discussion. This is not a place where one hides under that excuse. For pink noise to garner nearly 100% confident differences in double blind testing, as they did in Meyer's testing, one or both amps are deviating from anything that we would envision a linear amplifier to do: add gain without any colorations.
"music" did not act as revealing probe signal. A couple of tracks picked at random by a tester does not constitute a proper test.
Amir, please reveal the means by which musical test tracks were selected for this highly publicized sighted evaluation that you have staked your reputation and the reputation of your business on:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
"Reinventing the Audio Power Amplifier: Mark Levinson No 53"
By Amir Majidimehr
The problem is Steven, our esteemed member Arny, has proven that high-power solid state amps sound different:
If two amplifiers sound different on pink noise, they are different sounding. Period. End of discussion.
An even bigger problem Amir, is you claim amps sound different here:
(http://i216.photobucket.com/albums/cc73/AJinFLA/MadronaML53amp.jpg)
...but provide zero info on test methods or material used, music or pink noise.
Very much a amateurish hobbyist type mistake for such a paper/claim.
cheers,
AJ
Amir, please reveal the means by which musical test tracks were selected for this highly publicized sighted evaluation that you have staked your reputation and the reputation of your business on:
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
"Reinventing the Audio Power Amplifier: Mark Levinson No 53"
By Amir Majidimehr
Perhaps he used pink noise? Or maybe some kind of spectrum analyzer program on his pc that could be used for many such things?
There is nothing to indicate setup or level matching method either. Very troubling for such a test and subsequent claims, given Amirs very public level matching method history:
listening test, described here (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method.html#post16216826), when he tested DACs back in 2001-02.
Originally Posted by amirm
The comparison I performed was using a Mark Levinson No360S against the on-board DACs in five to six DVD-A and SACD players, all playing the same time sync'ed CD. In other words, I would listen to the analog output of the player while its digital output would feed the ML DAC. All front panel lights were turned off in addition to video circuits (yes, all of that made a difference in fidelity).
The two sources were fed to the dual inputs of a Stax "earspeaker" electrostatic headphone amp. If you are not familiar with Stax, you can read learn more about them here: http://www.stax.co.jp/Export/ExportProducts.html (http://www.stax.co.jp/Export/ExportProducts.html). I have three of their units and results are consistent across the board although the highest end unit does make the job a bit easier. Using headphones allowed me to completely eliminate the room and take advantage of the amazing transparency of these headphones to listen for the slightest differences. To latter point, I would often listen to material at levels well above what I would use for listening to music, allowing me to hear detail that would otherwise be lost.
I then picked material that made it easier to detect differences between DACs. I am not going to disclose what constitutes such content. Without such material, the job can range from difficult to impossible. One has to know what could be damaged by a DAC and then use music that has such content. To give you an example, when you compress music, it is the transients that suffer. So something like guitar music is much more revealing than say, violin as the latter is much more harmonic than the sharp impulses of a guitar. Voices play the same role. None of these are useful for testing DACs though so don’t use that as a hint to the question posed . You can’t test the cornering of a car if you just drive it straight….
The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.
I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.
The results above were later objectively shown to be backed by some science in Stereophile magazine. In reviews of said players and Mark Levinson, it was shown that the former would only resolve to 14 or 15 bits of audio samples. Turning off the front panel pushed some up to 16 bits or so. The ML on the other hand, was tested to have equiv. of 19.5 bits. This is contrast to all the DACs being rated at "24 bits."
Now this testing is a few years old (probably circa 2001 to 2002). Maybe DACs have improved so much that the $20 part in the player is just as good as my then $8000 Mark Levinson DAC (which was hand tuned). If so, then I like to know who has tested the new ones and details of their methodology.
There you have it. Was it worth the wait?
Amir, hopefully it will be worth our wait when you explain how you ran these amp distortion comparison tests of yours. Guess we'll just have to keep asking.
cheers,
AJ
And the beauty part is: it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (the only situation here where *music* acted as a revealing probe signal)
"music" did not act as revealing probe signal. A couple of tracks picked at random by a tester does not constitute a proper test.
Like the one you did with your Mark Levinson amp?
Music is what most people listen to over their audio systems. Most people, if they could hear a difference with a test tone, but not with music, wouldn't care about the former. They'd care if they could hear it with music, though. But you're special, I know.
If two amplifiers sound different on pink noise, they are different sounding. Period. End of discussion. This is not a place where one hides under that excuse. For pink noise to garner nearly 100% confident differences in double blind testing, as they did in Meyer's testing, one or both amps are deviating from anything that we would envision a linear amplifier to do: add gain without any colorations.
I see. So, if difference can be perceived under *some* circumstance, it is perceived in *all*?
You've heard of masking, right? Perception of sonic difference dependent on absence of other sounds?
Also, I'm with you on the 'envisioning a linear amplifier' thing: I would call that tube amp's behavior *intentionally pathological*. And again, no one here, or elsewhere, is claiming that tube amps fit the definition of 'amps that are likely to sound the same'.
And the beauty part is: it's also a rather far more common case for any two random setups than, say, happening upon an SS amp vs a tube amp as the top halves of two biamped setup (the only situation here where *music* acted as a revealing probe signal)
"music" did not act as revealing probe signal. A couple of tracks picked at random by a tester does not constitute a proper test.
Music is what most people listen to over their audio systems.
No, two tracks does not equate "music." You must demonstrate that those two tracks are revealing of frequency response variations which is what he has testing. His data clearly shows that pink noise did that and his selected music clips did not. We have objective data here on which is the right answer: it was the pink noise.
Most people, if they could hear a difference with a test tone, but not with music, wouldn't care about the former. They'd care if they could hear it with music, though. But you're special, I know.
For amplifiers you better care if you hear it with a tone just the same.
If two amplifiers sound different on pink noise, they are different sounding. Period. End of discussion. This is not a place where one hides under that excuse. For pink noise to garner nearly 100% confident differences in double blind testing, as they did in Meyer's testing, one or both amps are deviating from anything that we would envision a linear amplifier to do: add gain without any colorations.
I see. So, if difference can be perceived under *some* circumstance, it is perceived in *all*?
Where did you get "all" from? If an amplifier is coloring the sound with pink noise, then it has the ability to do that with some selection of music or music segments just the same. That you didn't get lucky with a couple of tracks to hear them doesn't change that fact at all.
You've heard of masking, right? Perception of sonic difference dependent on absence of other sounds?
Masking is not the issue here with respect to linear frequency response variations. If I insert an eq and boost 2 Khz by 2 db, whether you hear it or not is a statistical problem: does your music have sufficient energy in that frequency for it to be audible. See this article I wrote on that based on excellent work from Dr. Toole on Audibility of Resonances: http://www.madronadigital.com/Library/Audi...istortions.html (http://www.madronadigital.com/Library/AudibilityofSmallDistortions.html)
Coloration of this type is not distortion where you could talk about masking hiding the introduced distortion products.
Also, I'm with you on the 'envisioning a linear amplifier' thing: I would call that tube amp's behavior *intentionally pathological*. And again, no one here, or elsewhere, is claiming that tube amps fit the definition of 'amps that are likely to sound the same'.
Good. We are in agreement here .
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
"Reinventing the Audio Power Amplifier: Mark Levinson No 53"
By Amir Majidimehr
Amir, hopefully it will be worth our wait when you explain how you ran these amp distortion comparison tests of yours. Guess we'll just have to keep asking.
Why do you assume that by repeating your question it gets you the explanation?
http://www.madronadigital.com/Library/Mark...3Amplifier.html (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
"Reinventing the Audio Power Amplifier: Mark Levinson No 53"
By Amir Majidimehr
Amir, hopefully it will be worth our wait when you explain how you ran these amp distortion comparison tests of yours. Guess we'll just have to keep asking.
Why do you assume that by repeating your question it gets you the explanation?
Because repeating it did get us a true explanation. If there was anything positive or scientific about how you did those tests you'd be trumpeting it from the rooftops. Since you are not doing that, past experience indicates that you are trying to hide the fact that the only substantiation you have are plain ordinary golden ear audiophile sighted non level-matched evaluations based on whatever music you picked by random.
The first few times we were unsure if you were able to comprehend what we were asking for given your track record for that, but the post above shows that you do understand our reasonable expectations, but are just stone-walling us to avoid taking responsibility for your anti-scientific work. We know that there is a positive relationship between how hard you obfuscate and how much you think you have to hide.
Why do you assume that by repeating your question it gets you the explanation?
Why do you assume your repeated evasions and dancing isn't providing explanations/answers?
Plus, we have precedence involved here. Your previous audibility "listening" comparison test. Prior art. Behold:
Originally Posted by amirm
The comparison I performed was using a Mark Levinson No360S against the on-board DACs in five to six DVD-A and SACD players, all playing the same time sync'ed CD. In other words, I would listen to the analog output of the player while its digital output would feed the ML DAC. All front panel lights were turned off in addition to video circuits (yes, all of that made a difference in fidelity).
The two sources were fed to the dual inputs of a Stax "earspeaker" electrostatic headphone amp. If you are not familiar with Stax, you can read learn more about them here: [url="http://www.stax.co.jp/Export/ExportProducts.html"]http://www.stax.co.jp/Export/ExportProducts.html (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method.html#post16216826). I have three of their units and results are consistent across the board although the highest end unit does make the job a bit easier. Using headphones allowed me to completely eliminate the room and take advantage of the amazing transparency of these headphones to listen for the slightest differences. To latter point, I would often listen to material at levels well above what I would use for listening to music, allowing me to hear detail that would otherwise be lost.
I then picked material that made it easier to detect differences between DACs. I am not going to disclose what constitutes such content. Without such material, the job can range from difficult to impossible. One has to know what could be damaged by a DAC and then use music that has such content. To give you an example, when you compress music, it is the transients that suffer. So something like guitar music is much more revealing than say, violin as the latter is much more harmonic than the sharp impulses of a guitar. Voices play the same role. None of these are useful for testing DACs though so don’t use that as a hint to the question posed . You can’t test the cornering of a car if you just drive it straight….
The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.
I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.
The results above were later objectively shown to be backed by some science in Stereophile magazine. In reviews of said players and Mark Levinson, it was shown that the former would only resolve to 14 or 15 bits of audio samples. Turning off the front panel pushed some up to 16 bits or so. The ML on the other hand, was tested to have equiv. of 19.5 bits. This is contrast to all the DACs being rated at "24 bits."
Now this testing is a few years old (probably circa 2001 to 2002). Maybe DACs have improved so much that the $20 part in the player is just as good as my then $8000 Mark Levinson DAC (which was hand tuned). If so, then I like to know who has tested the new ones and details of their methodology.
There you have it. Was it worth the wait?[/i]
See? It took
2 threads (thanks to Chu Gai for starting 2nd) before you divulged your listening test method for ML DACs.
Then, it took a full 14 pages and 400+ posts, before you admitted that it/the results were a farce (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16386041), an utter fabrication:
Originally Posted by amirm
Originally Posted by Terry Montlick View Post
And you derive this probable number from exactly what statistical test??
Nothing that complicated. I give it one out of three chances to be wrong, based on more than a decade of conducting double-blind and subjective tests and formal evaluations of my hearing. In other words, I know what percentage of time I have made a fool of myself in such tests . Versus being right.
You didn't answer my question on how many blind tests you have been involved in.
So their is precedence and ample reason to continue asking about your (ML) amp distortions audibility test, in the Audibility of Audio Power Amplifier Distortions thread.
I'm (we?) hoping it doesn't take 2 threads and 400+ posts to shed light on your amp "tests", but that's entirely up to you.
cheers,
AJ
No, two tracks does not equate "music."
I didn't say 'represents all possible music' . But Cowboy Junkies and the Bach Oratorio are both probably nice recordings (CJ had a reputation for high quality sound), what do you suggest as a revealing musical probe for conditions 2 and 3? Something mastered more modern-style with heavy compression, perhaps? Could even be a high rez recording!
You must demonstrate that those two tracks are revealing of frequency response variations which is what he has testing. His data clearly shows that pink noise did that and his selected music clips did not. We have objective data here on which is the right answer: it was the pink noise.
He *heard* the difference between SS and tube with *music* (as well as pink noise) in Condition 1 ( amps driving the top end of the biamped system) where the load resulted in a bump below 500Hz in the tube system, vs the SS system. So music was a sufficient probe for that. (It's unclear how many subjects were tested besides himself, so I say 'he')
In condition2 (same amps driving the same system full range) he reports no difference with music, did hear one with pink noise, and there was *no bump* in the <500 Hz FR but there was still some narrower-band FR differences e.g. dip circa 4kHz.
In condition 3, both amps driving a system that was a less difficult load, the FRs were even less different than before -- similar enough that no difference was heard with music and *barely any* with pink noise. Remember too that these tests included breaks for coffee, multiple ways of playing the material, etc... he/they were really trying hard.
In each case it's the tube amp that has the less flat FR....it's the less 'true' output compared to input.
You're suggesting that with different musical selections, the difference he heard with pink noise in 2, barely detectable with pink noise in 3, would also manifest with music.
Could be! But *I'd* say Meyer's showing evidence supporting two rather more practical conclusions: 1)
big FR differences due to a particular amp/speaker pairing are more likely to manifest audibly (with music or pink noise) than
small ones; 2) pink noise will more readily reveal small ones.
So: if you plan to listen to music, avoid amp/speaker pairings likely to result in big/broad deviations from flat FR. If you're into pink noise, be even more careful.
Seriously, you think this is a common danger? This all 'matters' only if we expect to encounter amps that behave like that tube amp (the SS behaved well *in all conditions*). How often do you think a random pair of amps will feature one behaving like that tube amp?
(I would say it's probably more likely in the *high end* where intentionally pathological hardware is sometimes 'recommended' )
So their is precedence and ample reason to continue asking about your (ML) amp distortions audibility test, in the Audibility of Audio Power Amplifier Distortions thread.
I'm (we?) hoping it doesn't take 2 threads and 400+ posts to shed light on your amp "tests", but that's entirely up to you.
I was looking at the Levinson 57 power amp pictures on the web and suddenly realized that a pair of them grace the pictures of his personal stereo system that Amir has posted on AVS.
Explains a lot, eh? ;-)
I was looking at the Levinson 57 power amp pictures on the web and suddenly realized that a pair of them grace the pictures of his personal stereo system that Amir has posted on AVS.
Explains a lot, eh? ;-)
Amir has said he does not have a personal stereo system at home, so he can't post any pictures of such. He's not a music lover/audiophile himself, he simply sees a market for and sells audiophile (vs "Mid-Fi") equipment. He claims to have a laptop at home where he analyses files. Mentioned something about a real time spectrum analyzer once, but I don't recall the details. Perhaps you're referring to this pic, which is at Madrona, which he pitched here in this amusing thread (http://www.avsforum.com/forum/91-audio-theory-setup-chat/1379651-cd-player-mid-fi-setup.html):
(http://amirviews.smugmug.com/photos/1243969019_v8BW2-XL.jpg)
There is no evidence that any comparison to AB/other class D amps ever actually took place, but I suppose it's possible this is where Amir "heard" the super bass/"neutrality" etc of the $50K+ MLs he peddles in that write up about amp distortions.
We still await the details, which perhaps are still in the making?
cheers,
AJ
Careful now, Arny. If you mention his name three times he'll appear just like in the movie Candyman.
He's not a music lover/audiophile himself, he simply sees a market for and sells audiophile (vs "Mid-Fi") equipment.
I do not. Anyone who sets up shop to sell high-end audio gear needs to either a) have his head examined or b) is much smarter than me in knowing how to make money from it. Retail audio business sucks and sucks big time. Here is the type of projects we do: http://www.madronadigital.com/Gallery/Gallery.html (http://www.madronadigital.com/Gallery/Gallery.html)
(http://www.madronadigital.com/Gallery/images/WaterfrontSeattleHome.jpg)
No audio equipment in sight, right? Well, there is. Custom made Triad speakers to our spec have been installed in a way you can't see them. There is a sub above the fireplace. The system is powered by a commercial Crown amplifier with its DSP programmed for best in-room response. Client enjoys music and loves it. If you showed up with the speakers you sell they would throw you out of the room. You can read the story behind that and more in this article I wrote for Widescreen Review Magazine: http://www.madronadigital.com/Library/Arch...turalAudio.html (http://www.madronadigital.com/Library/ArchitecturalAudio.html)
Here is the rack of crown amplifiers used to power the Bellevue Mercedes dealership:
(http://www.madronadigital.com/Gallery/images/BarrierCrown.jpg)
You can read the story behind the innovations in their system in this other article I wrote: http://www.madronadigital.com/Library/Barr...rcedesBenz.html (http://www.madronadigital.com/Library/BarrierMercedesBenz.html)
We also did the audio system for the Seattle Wheel (our version of London Eye): http://www.madronadigital.com/Library/Seat...at%20Wheel.html (http://www.madronadigital.com/Library/Seattle%20Great%20Wheel.html)
(http://www.madronadigital.com/Library/GreatWheelofSeattle.jpg)
We used CBT speakers to reduce the sharp drop off from distance to the speaker as people wait in line.
A high-end project for us is $500,000. $100,000 of it will be for automated lighting and shade if not more. There will be nothing for any kind of high-end gear. We are Harman's largest dealer on the west coast but that comes from selling hundreds of Crown amplifiers for whole house audio distribution and zero for selling Mark Levinson.
The above is where the money is dear Ammar. If you have figured out how to make money selling high-end gear, by all means, set up shop and come and tell us how you have managed to do that. Madrona Digital's business is not that. We are an engineering company specializing in solving tough problems in custom residential and commercial projects. Evidence of that is all over the company's web site.
Careful now, Arny. If you mention his name three times he'll appear just like in the movie Candyman.
Five times...
Three times was Beetlejuice.
He claims to have a laptop at home where he analyses files.
You don't think I have one Ammar?
Mentioned something about a real time spectrum analyzer once, but I don't recall the details.
Happy to provide you detail. Here is my setup for the comprehensive measurement of digital audio in AVRs and Processors:
(http://amirviews.smugmug.com/photos/i-T8VfGXr/0/X3/i-T8VfGXr-X3.jpg)
There are not one but two audio analyzers in that picture. One is almost hidden behind the laptop and it is an Audio Precision analyzer which when I bought it originally, it cost about $25,000. There is another one behind and to the right of the laptop and it is from Prism Sound and retails about $9,000. So those two combined are about $34,000 in "real time analyzers." You get pretty measurements like this out of them:
(http://amirviews.smugmug.com/photos/i-8X8ksRF/0/X2/i-8X8ksRF-X2.png)
Showing distortion sidebands you don't know are there (this is from a $400 DAC).
This is my other workstation where I measured Performance of Speaker Wires (http://www.whatsbestforum.com/showthread.php?14134-When-12-Gauge-Wire-is-not-12-Gauge)!: http://www.whatsbestforum.com/showthread.p...is-not-12-Gauge (http://www.whatsbestforum.com/showthread.php?14134-When-12-Gauge-Wire-is-not-12-Gauge)!
(http://amirviews.smugmug.com/photos/i-4QWLZhN/0/O/i-4QWLZhN.jpg)
Visible there are my Agilent Scope and Spectrum analyzer. Next to it is my Rigol signal generator. I post measurements of amplifiers clipping like this hideous class D AVR:
(http://amirviews.smugmug.com/photos/i-gbnBR4Z/0/X2/i-gbnBR4Z-X2.png)
You also see a bunch of multi-meters but a couple of them are special in the way they can measure very small resistance (useful of course for short segments of speaker wire).
I don't have a picture to show you but I am now a proud owner of a Tektronix mixed-domain scope and 3 Ghz spectrum analyzer:
(http://d31c9fxmn9e6zf.cloudfront.net/media/catalog/category/Tektronix_MDO3012_Landing_Page.jpg)
Its spectrum analyzer does not have enough dynamic range for audio but will be wonderful to measure many other things.
Trust this is sufficient "detail" to get us past this argument.
The above is where the money is dear Ammar.
Jeez Amir, all I said was you have no home stereo and you respond with that irrelevant epic...
He claims to have a laptop at home where he analyses files.
You don't think I have one Ammar?
Mentioned something about a real time spectrum analyzer once, but I don't recall the details.
Happy to provide you detail. Here is my setup for the comprehensive measurement of digital audio in AVRs and Processors:
cheers,
AJ
Amir, I have never ever doubted you having spectral analysis capability on your home laptops.
Then you need to look up the meaning of the word "claim" in the dictionary because you said this:
"He claims to have a laptop at home where he analyses files."I was just curious about the specific program used concurrently when running those "Hi Re$" ABX test files is all. Thanks for those details shown anyway.
You could have asked. Answer is that I don't use any program while running ABX files. I drag the files into foobar playlist and select them to perform the ABX. That is it.
If I need to perform software analysis, I use Adobe Audition CC.
Now of course, that brings us no closer to how you did your ML 53 vs .....amp distortion audibility comparisons.
It did not but maybe you learned not to shoot from the hip without having any data .
We certainly know how you did DAC comparisons
There is a lot more recent objective work I have done in that area. I have shown you some of that before. Here is more.
Take a look at this measurement:
[/quote]
Oh you did ask by implying that my company is in the business of selling high-end gear and that biases my views. Had to set the record straight there.
You could have asked.
We've "asked" for an entire thread about Audibility of Audio Power Amplifier Distortions, for you to show your claimed tests of Audibility of Audio Power Amplifier Distortions...and the answer is obfuscation and dancing to avoid showing how you've done "comparisons" from 2001 (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method-14.html#post16385882) to 2011 (http://www.whatsbestforum.com/showthread.php?3211-Review-Benchmark-DAC1-%28Modified%29&p=48449&viewfull=1#post48449). So no sense in asking directly about spectral analysis of ABX files either.
Answer is that I don't use any program while running ABX files. I drag the files into foobar playlist and select them to perform the ABX. That is it.
You need to look up the meaning of the word "claim" in the dictionary.
If I need to perform software analysis, I use Adobe Audition CC.
Not familiar with the program or whether it can be run real time concurrently....for software file analysis.
Oh you did ask by implying that my company is in the business of selling high-end gear and that biases my views.
(http://amirviews.smugmug.com/photos/1243969019_v8BW2-XL.jpg)
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
By Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
While you're looking up the meaning of the word "claim" in the dictionary, please also look up "imply".
cheers,
AJ
While you're looking up the meaning of the word "claim" in the dictionary, please also look up "imply".
Seems pretty clear to me that in some people's minds right and reasonable is based on what they believe and want, and is not limited to the application of reason or science. IME one sees this behavior among people who have successfully ascended the corporate ladder in some large successful organization or the other. If allowed to become widespread, the whole organization suffers. Time for housecleaning!
We've "asked" for an entire thread about Audibility of Audio Power Amplifier Distortions, for you to show your claimed tests of Audibility of Audio Power Amplifier Distortions...
Claimed tests? This is not a claim:
(http://amirviews.smugmug.com/photos/i-NVbTMcL/0/X2/i-NVbTMcL-X2.png)
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other? If so, let's have you and Arny go at it.
Or perhaps you doubt this from our esteemed double blind tester, Mr. Meyer:
(http://amirviews.smugmug.com/photos/i-n3vhLWb/0/X2/i-n3vhLWb-X2.png)
Please confirm if you believe or doubt the validity of above. Because if you do, we will stay here forever with respect to your requests.
We've "asked" for an entire thread about Audibility of Audio Power Amplifier Distortions, for you to show your claimed tests of Audibility of Audio Power Amplifier Distortions...
Claimed tests? This is not a claim:
(http://amirviews.smugmug.com/photos/i-NVbTMcL/0/X2/i-NVbTMcL-X2.png)
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other? If so, let's have you and Arny go at it.
Or perhaps you doubt this from our esteemed double blind tester, Mr. Meyer:
(http://amirviews.smugmug.com/photos/i-n3vhLWb/0/X2/i-n3vhLWb-X2.png)
Please confirm if you believe or doubt the validity of above. Because if you do, we will stay here forever with respect to your requests.
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
We've "asked" for an entire thread about Audibility of Audio Power Amplifier Distortions, for you to show your claimed tests of Audibility of Audio Power Amplifier Distortions...
Claimed tests? This is not a claim:
(http://i216.photobucket.com/albums/cc73/AJinFLA/MadronaML53amp.jpg)
We know. It's a highly specious BS statement made by a subjectivist, with zero basis, zero objective science and highly likely a complete fabrication based on documented history.
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
By Amir Majidimehr
In comparison testing I have done, switching amplifiers using the classic class D configuration always sport incredible low frequency control and power. They beat out linear class AB amplifiers almost regardless of price. What they give up though is high frequency fidelity which I find somewhat harsh. The distortion is highly non-linear and challenging to spot but it is there. The Mark Levinson No 53 is the first switching amplifier I have heard which does not have this compromise. Its bass is amazingly authoritative: tight and powerful. Yet the rest of the response is absolutely neutral and pleasant.
If you have not heard these unique amplifiers, I highly encourage you to come into our showroom for a listen. We have a pair on hand driving our Revel speakers. I am confident that they will improve the sound of your current speakers given the ease with which they can drive any load regardless of how difficult they might be (and many high-end speakers are difficult to drive). We are happy to let you evaluate them with your own system to see the benefits of this technology. Hearing this amplifier was an eye-opener for me. I think it will be for you too.
Or perhaps you doubt this from our esteemed double blind tester, Mr. Meyer:
No. I doubt this from our self assessed "objectivist 'our' camp" not at all single/double/any blind tester, Mr. Majidimehr:
http://www.avsforum.com/forum/86-ultra-hi-...ml#post16216826 (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method.html#post16216826)
The comparison was then conducted without knowing which input is which, sitting in front of the headphone amp and toggling back and forth. When necessary, I would go back and re-listen. Once I found which one sounded worse, I would then repeat the exercise by randomizing the inputs and seeing if I could still identify which one was worse. My success rate was 100% in the second test (i.e. could always verify that the first result was not by chance). This testing was repeated a number of times comparing the different sources against each other and the ML.
I did not level match anything. However, once I found one source was worse than the other, I would then turn up the volume to counter any effect there. Indeed, doing so would close the gap some but it never changed the outcome. Note that the elevated level clearly made that source sound louder than the other. So the advantage was put on the losing side.
The results above were later objectively shown to be backed by some science in Stereophile magazine. In reviews of said players and Mark Levinson, it was shown that the former would only resolve to 14 or 15 bits of audio samples. Turning off the front panel pushed some up to 16 bits or so. The ML on the other hand, was tested to have equiv. of 19.5 bits. This is contrast to all the DACs being rated at "24 bits."
Now this testing is a few years old (probably circa 2001 to 2002). Maybe DACs have improved so much that the $20 part in the player is just as good as my then $8000 Mark Levinson DAC (which was hand tuned). If so, then I like to know who has tested the new ones and details of their methodology.
There you have it. Was it worth the wait?
http://www.whatsbestforum.com/showthread.p...Audio-Alpha-USB (http://www.whatsbestforum.com/showthread.php?4160-Review-Berkeley-Audio-Alpha-USB)
Note 1: This is a purely subjective review. It is entirely possible that my conclusions are wrong. Certainly the power of placebo is far higher than the small differences I hear. In my short testing, and the way these devices work, it is hard to set up the type of objective tests I like to have to reduce the effects of bias.
Note 2: My company carries the Berkeley audio products and in previous life, I acquired Pacific Microsonics/HDCD which was founded by the same people behind this product.
What did I hear? First, on many tracks nothing. As I mentioned, on a lot of material the difference is either not there or if it is, it is too small to rely on it existing in such an ad-hoc test. Where it did surface, it was predictable. The high frequencies were slightly cleaner. And ambiance and decay more pronounced which impacts the perceived soundstage of music/instruments. I hate to use this word but I can’t think of any other to way that the overall experience was more “analog like” in the sense of it sounding more pleasant.
I found the difference easiest to hear on my audiophile A-DVD 24-bit, 96 Khz tracks. Perhaps due to higher sampling rate, jitter reduction matters more. Or else, these are just better recordings so the difference is easier to hear.
For the objectivists in the crowd, the difference was never night and day. All three interfaces were dynamic, and were enjoyable to listen. The Berkeley and Audiophilleo simply added a bit more fidelity on top. It is like putting some pepper on a good stake .
Please confirm if you believe or doubt the validity of above.
I confirm I have no doubt that all your so called listening comparison tests are subjectivist daydreams or fabrications and I believed you when you admitted so in the +/-10% volume fiasco, plus confessed to being a subjectivist and referring to objectivists as other camp in the Berkley "review".
However, there is no such admission or stipulation in the Audibility of Audio Power Amplifier Distortions tests you claim to have done here:
(http://i216.photobucket.com/albums/cc73/AJinFLA/MadronaML53amp.jpg)
Zero preface about it being either a purely subjectivist "review" (Berkley), or an outright fabrication (+/- 10% fiasco). It's on your website.
Now it's up to you to show the goods in this Audibility of Audio Power Amplifier Distortions thread. Or the questions keep coming.
cheers,
AJ
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
Arny, why do you keep answering on his behalf over and over again? I asked him some simple questions and I like him to answer. You and he are not equally situated in this topic, are you?
Are afraid he may say the wrong thing?
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
There is no indication your ML53 tests were double bind, single blind, +/-10% volume "forget to remember input" blind, subjectivist daydream sighted...or just an outright fabrication.
Nor source used. TT? I thought you used Hi-Re$ files if you're concocting stories like this?
If that test was not run and you didn't know said outcome, what would have been your position?
Shock. No, just kidding.
I think we both know you didn't run any ML vs Class D/AB amps "tests", outside of perhaps some sighted subjectivist shenanigans/blathering like with the Berkley.
That they can or cannot sound different?
(http://amirviews.smugmug.com/photos/1243969019_v8BW2-XL.jpg)
(http://i216.photobucket.com/albums/cc73/AJinFLA/MadronaML53amp.jpg)
Because something "can" sound different, is not proof that you demonstrated audible power amp difference between ML53 and other Class D/AB, which is precisely what you claim and continue to claim at your sales store. That might sell to the audiomoron, but not a rational person. For an objectivist or anyone with a conscience/ethics, it would be despicable.
It's blatantly false advertising....but as you say, like BS, you know the business side of this field.
cheers,
AJ
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
Arny, why do you keep answering on his behalf over and over again?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
Arny, why do you keep answering on his behalf over and over again?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
(http://amirviews.smugmug.com/photos/i-zwGKV6C/0/O/i-zwGKV6C.png)
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
Arny, why do you keep answering on his behalf over and over again?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
(http://amirviews.smugmug.com/photos/i-zwGKV6C/0/O/i-zwGKV6C.png)
Then why bother posting on a forum where one is expected to confirm and affirm their claims?
You doubt the "indisputable proof" that solid state amplifiers can sound different from each other?
No. We doubt your "indisputable proof" that the ML53 Class D amplifier sound different from other Class D and AB solid state amplifiers, as you claim here to have done/proven:
Reinventing the Audio Power Amplifier: Mark Levinson No 53 (http://www.madronadigital.com/Library/MarkLevinsonNo53Amplifier.html)
Ah we are getting some place. So to confirm, you accept that two high power solid state amplifiers in double blind ABX tests with turntable no less, were found to sound different in two out of three tracks. Right?
If that test was not run and you didn't know said outcome, what would have been your position? That they can or cannot sound different?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
Arny, why do you keep answering on his behalf over and over again?
Amir, please confirm that you actually understand the irrelevancy of the above comments to our discussion of your proud flaunting of bogus sighted evaluations of power amplifiers.
(http://amirviews.smugmug.com/photos/i-zwGKV6C/0/O/i-zwGKV6C.png)
Then why bother posting on a forum where one is expected to confirm and affirm their claims?
You seriously holding me accountable for what Bart Simpson wrote on a chalkboard? The dude is much smarter than me:
(http://amirviews.smugmug.com/photos/i-9LTmF2z/0/X3/i-9LTmF2z-X3.jpg)
Not sure how you can confuse the two of us.
Not sure how you can confuse the two of us.
There is no confusion because even I can tell the difference between a cartoon character and a Turing-Test compliant human being, even when the human goes out of his way to emulate the 'toon.
However behavior that is funny when acted out by a 'toon is often pretty pathetic when acted out by a person.
You seriously holding me accountable for what Bart Simpson wrote on a chalkboard?
Nope, Bart didn't spew this subjectivist
amplifier distortion audibility "comparison" crap, you did:
(http://i216.photobucket.com/albums/cc73/AJinFLA/MadronaML53blathering.png)
You've been trying to hold Arny and M&Ms feet to the fire and now it's your turn to answer about your test methods beyond your "business side of things" DAC daydreams
(http://i216.photobucket.com/albums/cc73/AJinFLA/WTF.jpg)
...and outright fabrications (http://www.avsforum.com/forum/86-ultra-hi-end-ht-gear-20-000/1136745-establishing-differences-10-volume-method.html)
cheers,
AJ
Topic closed. See http://www.hydrogenaud.io/forums/index.php...st&p=883786 (http://www.hydrogenaud.io/forums/index.php?s=&showtopic=107124&view=findpost&p=883786)