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.

Your evasion provides the answers.
[...]
p.s., ignoring and evading answers....provide answers also.

I will go ahead and answer  the questions

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.

That didn't happen with AJ so we have to deal with him as appropriate.

Quote from: ajinfla on 2014-11-30 01:03:05

Quote from: amirm on 2014-11-30 00:58:07

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, the thread title.

What happens if I don't Ammar?

Quote from: amirm on 2014-11-30 01:48:56

Quote from: ajinfla on 2014-11-30 01:03:05

Quote from: amirm on 2014-11-30 00:58:07

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, 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.

Quote from: ajinfla on 2014-11-30 02:07:30

Quote from: amirm on 2014-11-30 01:48:56

Quote from: ajinfla on 2014-11-30 01:03:05

Quote from: amirm on 2014-11-30 00:58:07

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, 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?

Quote from: ajinfla on 2014-11-30 02:07:30

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?

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.

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

Quote

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.

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. 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?

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
[...]
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.

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.

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

It's like faulting Henry Ford's first prototype car because of the styling of the fenders.

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.

Back to this thread

Since it seems impossible for you to stay on topic and turning everything into train wrecks....

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.

, 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):

you evading a simple 4 second test file since over a week ago

Quote from: amirm on 2014-11-22 18:42:49

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.  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. 

Quote

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.

Quote

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.

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...

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.

I have been very clear that I am not at all uncomfortable with anything I have written or you have said about it.

http://www.madronadigital.com/Library/Mark...3Amplifier.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.

As to the "unwilling to discuss" part, there is good reason for that.

Back to this thread, you are demanding that I tell you more about my amplifier tests.

http://www.madronadigital.com/Library/Mark...3Amplifier.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?

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?

It takes incredible amount of time and energy to run these tests Ammar.

http://www.madronadigital.com/Library/Mark...3Amplifier.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.

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.

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.

http://www.madronadigital.com/Library/Mark...3Amplifier.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.

As I promised Steven earlier, here are some additional quotes from the Meyer amplifier test.

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

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 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.

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?

Quote from: Chu Gai on 2014-11-30 23:53:46

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.

Quote from: Arnold B. Krueger on 2014-11-30 12:46:12

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:

Quote from: Arnold B. Krueger on 2014-11-30 13:09:10

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:

Quote from: Arnold B. Krueger on 2014-11-26 22:04:41

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?

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 judgments 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.

Quote from: Chu Gai on 2014-11-30 23:53:46

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.