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Topic: Cracked cones (Read 6428 times) previous topic - next topic
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Cracked cones

A few days ago I was listening some music, and my right speaker start doing some noise, like something was vibrating REALLY bad against it. So I take a look at these speakers, and what do I see? The cones (yeah, the actual cone, not the rubber stuff around it) is all cracked. The speakers are floorstanding Mission 733s, which were bought roughly 8 years ago. Is this normal wear (this appears to be the general consensus of stores around here)? If not what caused this?

Now, my main question is, what should I do with this? I went to the store where I originally bought them, and they said that the warranty on them (5 years) was over, and that ordering some replacement speakers (just the two 6.5") from mission would be pretty much the same price as buying a brand new set of floorstanders. They also said they could send them to some mission service center (or something like that) for a 100$/speaker suspension rebuild.

Another smaller store I visited offered either rebuilding the suspension themselves for 50$, or some selling me these "Bele" 6.5 speakers for 30$ each that are apparently their best sounding replacement speakers. The salesman assured me that they would sound just as good, but I am skeptical about that.

Me being not too knowledgeable about this (and having bought these speakers hoping they would last longer thant this), I'm a bit confused about all that. None of the stores I visited seemed very helpful. So I'm turning to you guys, what should I do with this cracked speaker?

Cracked cones

Reply #1 –
Quote
A few days ago I was listening some music, and my right speaker start doing some noise, like something was vibrating REALLY bad against it. So I take a look at these speakers, and what do I see? The cones (yeah, the actual cone, not the rubber stuff around it) is all cracked. The speakers are floorstanding Mission 733s, which were bought roughly 8 years ago. Is this normal wear (this appears to be the general consensus of stores around here)? If not what caused this?

Now, my main question is, what should I do with this? I went to the store where I originally bought them, and they said that the warranty on them (5 years) was over, and that ordering some replacement speakers (just the two 6.5") from mission would be pretty much the same price as buying a brand new set of floorstanders. They also said they could send them to some mission service center (or something like that) for a 100$/speaker suspension rebuild.

Another smaller store I visited offered either rebuilding the suspension themselves for 50$, or some selling me these "Bele" 6.5 speakers for 30$ each that are apparently their best sounding replacement speakers. The salesman assured me that they would sound just as good, but I am skeptical about that.

Me being not too knowledgeable about this (and having bought these speakers hoping they would last longer thant this), I'm a bit confused about all that. None of the stores I visited seemed very helpful. So I'm turning to you guys, what should I do with this cracked speaker?
[a href="index.php?act=findpost&pid=369437"][{POST_SNAPBACK}][/a]

Speaker cones don't usually crack unless they are very old or abused. What are the cones made of? Most low/mid qualities use paper, sometimes "rubberised" or plastic coated. Higher end tend to be plastic or even metal since it's more rigid and not susceptible to humidity. In any case, the suspension is more likely to fail through age than the cone itself. I'd say this is unusual.

As for what can be done, speakers can be re-coned but it needs a good specialist and probably costs quite a bit. You could try to establish the speaker manufacturer (as opposed to the cabinet maker, Mission) and try to get a replacement or a pair of replacement equivalents but that'll be a bit pot-luck if it's possible. Not much else I can think of...

Cracked cones

Reply #2 –
Thanks for the reply. The cone, as far as I can tell, feels like plasticky paper. I called up a big mission distributor today. I asked them about the speaker's manufacturer, and they said that these speakers were made exclusively for mission and are not sold sperately, so the only way to get them is through mission. They said that they should be able to get me a pair for 80$/speaker plus shipping (wow! quite far from the 500$/speaker my dealer asked me), but that due to the acquring of mission by IAG and the age of these speakers, they are having trouble getting them. So I'm calling back in 3-4 weeks and hopefully by them they should know positively if they can still get them. Kinda long wait, but I'm hoping for the best .

As for reconing, yeah, the guy who offered it to me yesterday claims he has the capabilities to do it. However, he says that the cone material would not be the same (he talked about some membrane material?) and that this would affect the sound. So I'm not sure of that would be worth it.

Any other input still appreciated! Especially if you know you know a mission distributor/retailer/etc. in Canada that could potentially get me these speakers (for a reasonable price).

Cracked cones

Reply #3 –
Regardless of your replacement route, know tha JBL always includes a little pamphlet when it sends replacement speakers.  It warns of using too underpowered amps to drive the speakers.  Yes.  The underpowered amps clip and send a square wave to the speakers which cannot reproduce a square wave, or at least not for long.

So, buy bigger amps, too.  Or, do not turn it up so damned loud.  Your choice. 
Nov schmoz kapop.

Cracked cones

Reply #4 –
I haven't paid attention for years but I suspect there are still quite a few companies making all sorts of parts for DIY speaker builders. There are cone replacement supplies and complete kits and lots of replacements drivers. Unless you have a strong emotional need to stick with 'genuine Mission' parts there is a reasonable chance you can find something as good or better.

Cracked cones

Reply #5 –
Quote
Thanks for the reply. The cone, as far as I can tell, feels like plasticky paper. I called up a big mission distributor today. I asked them about the speaker's manufacturer, and they said that these speakers were made exclusively for mission and are not sold sperately, so the only way to get them is through mission. They said that they should be able to get me a pair for 80$/speaker plus shipping (wow! quite far from the 500$/speaker my dealer asked me), but that due to the acquring of mission by IAG and the age of these speakers, they are having trouble getting them. So I'm calling back in 3-4 weeks and hopefully by them they should know positively if they can still get them. Kinda long wait, but I'm hoping for the best .

As for reconing, yeah, the guy who offered it to me yesterday claims he has the capabilities to do it. However, he says that the cone material would not be the same (he talked about some membrane material?) and that this would affect the sound. So I'm not sure of that would be worth it.

Any other input still appreciated! Especially if you know you know a mission distributor/retailer/etc. in Canada that could potentially get me these speakers (for a reasonable price).
[a href="index.php?act=findpost&pid=369793"][{POST_SNAPBACK}][/a]

Go for the originals then, if possible. It's probably better to have both drivers re-coned rather than just one, if you take that route. The sound might not be affected that much and it might even improve if the new material is more rigid.

Despite being told they were "exclusive" to Mission, you may be able to get the same or very close equivalents. You'd need access to a bit of information on the original drivers, however, and that might not be so easy to get hold of. You'd need to know the resonance frequency and recommended loading, plus of course the power-handling ratings. Resonance frequency, in particular, would need to be very close to the original.

Cracked cones

Reply #6 –
Eight year old drivers shouldn't do this, so it's got to make you wonder about the rest of the speaker box design.

Check out a place like Parts Express for new drivers. Reconing is a waste on anything except well-engineered drivers like JBL Professional.

Cracked cones

Reply #7 –
Do the speakers spend a lot of time in direct sunlight? Without grills?

R.

Cracked cones

Reply #8 –
Quote
Regardless of your replacement route, know tha JBL always includes a little pamphlet when it sends replacement speakers.  It warns of using too underpowered amps to drive the speakers.  Yes.  The underpowered amps clip and send a square wave to the speakers which cannot reproduce a square wave, or at least not for long.

So, buy bigger amps, too.  Or, do not turn it up so damned loud.  Your choice.  
[a href="index.php?act=findpost&pid=369801"][{POST_SNAPBACK}][/a]


That could be possible. The amp is 65w/chan max and I rarely turn it up over 6 or so (max is 10), while the speakers have an output of 20-100w/chan...

Quote
Quote
Thanks for the reply. The cone, as far as I can tell, feels like plasticky paper. I called up a big mission distributor today. I asked them about the speaker's manufacturer, and they said that these speakers were made exclusively for mission and are not sold sperately, so the only way to get them is through mission. They said that they should be able to get me a pair for 80$/speaker plus shipping (wow! quite far from the 500$/speaker my dealer asked me), but that due to the acquring of mission by IAG and the age of these speakers, they are having trouble getting them. So I'm calling back in 3-4 weeks and hopefully by them they should know positively if they can still get them. Kinda long wait, but I'm hoping for the best .

As for reconing, yeah, the guy who offered it to me yesterday claims he has the capabilities to do it. However, he says that the cone material would not be the same (he talked about some membrane material?) and that this would affect the sound. So I'm not sure of that would be worth it.

Any other input still appreciated! Especially if you know you know a mission distributor/retailer/etc. in Canada that could potentially get me these speakers (for a reasonable price).
[a href="index.php?act=findpost&pid=369793"][{POST_SNAPBACK}][/a]

Go for the originals then, if possible. It's probably better to have both drivers re-coned rather than just one, if you take that route. The sound might not be affected that much and it might even improve if the new material is more rigid.

Despite being told they were "exclusive" to Mission, you may be able to get the same or very close equivalents. You'd need access to a bit of information on the original drivers, however, and that might not be so easy to get hold of. You'd need to know the resonance frequency and recommended loading, plus of course the power-handling ratings. Resonance frequency, in particular, would need to be very close to the original.
[a href="index.php?act=findpost&pid=369909"][{POST_SNAPBACK}][/a]


I have no idea where I could get these specs so I guess I'm kinda out of luck  All I have is the mission model number on the back of the driver.

Quote
Eight year old drivers shouldn't do this, so it's got to make you wonder about the rest of the speaker box design.

Check out a place like Parts Express for new drivers. Reconing is a waste on anything except well-engineered drivers like JBL Professional.
[a href="index.php?act=findpost&pid=370051"][{POST_SNAPBACK}][/a]


Hmmm. I don't getting other drivers than the official mission ones, however I would like to at least keep the sound quality I had (or even better get higher quality ). Now like I said I don't know much about this but isn't the case 'tuned' for these specific drivers? Wouldn't I have to get very similar drivers? And if that is the case, how would I go about finding what type of driver I need?

Quote
Do the speakers spend a lot of time in direct sunlight? Without grills?

R.
[a href="index.php?act=findpost&pid=370053"][{POST_SNAPBACK}][/a]


They might have spent a bit of time in sunlight, but the grills were always on. It could be plausible that sunlight did it, since the left one (the good one) was not exposed much, if at all, to sunlight.

The cone from the right driver (the bad one) seems 'dried out' and has become extremely fragile. Barely touching it causes little cracks to appear. No surprise that vibration from music caused it to crack all over...

Cracked cones

Reply #9 –
If this were my problem I would contact a number of driver manufacturers and DIY suppliers and see what kind of information they have. Once upon a time, when I had that interest, I saw more than a few offerings claiming to be "direct replacements" or superior replacements, for name brand speakers. Your drivers just might hapen to be fairly well know in the business.

Cracked cones

Reply #10 –
Quote
Regardless of your replacement route, know tha JBL always includes a little pamphlet when it sends replacement speakers.  It warns of using too underpowered amps to drive the speakers.  Yes.  The underpowered amps clip and send a square wave to the speakers which cannot reproduce a square wave, or at least not for long.

So, buy bigger amps, too.  Or, do not turn it up so damned loud.  Your choice.  
[{POST_SNAPBACK}][/a]
Not to hijack the thread, but here's a [a href="http://sound.westhost.com/tweeters.htm]good explanation of that scenario[/url].

Cracked cones

Reply #11 –
Here is my recommendation: 
First, go to your local music store.  Ask them where the best place in town is to get speakers reconed.  The music stores will always know because guitar players are notorious for blowing up the speakers in their guitar amps.

If that doesn't work:
Ask the manufacturer for the Theile-Small parameters, they are a sort of list of "statistics" for the speakers, they basically tell you how big of a speaker cabinet you need for that speaker.
The Thiele Small parameters will look sorta like this:
Le: 1.0 mH
Znom: 8 ohms
Re: 6.4 ohms
Frequency range: 27-2,000 Hz
Fs: 27 Hz
SPL: 88.1 dB 2.83V/1m
Vas: 2.75 cu. ft.
Qms: 1.60
Qes: .47
Qts: .37
Xmax: 7 mm

Once you find out that info, go to www.partsexpress.com, or www.mcmelectronics.com and look for a speaker that has statistics that are very similar to the broken speaker.  If they aren't too expensive, buy a pair and replace both speakers.

Oh, any place that recones speakers is usually able to provide you the T-S statistics if the manufacturer can't.  They have to put it on their test equipment, so it will probably cost 10 or 20 bucks.

Last alternative:
Remove speaker.  Cut some very, very, thin tissue paper (not toilet paper, not kleenex, not paper towels, not typing paper) to make a bandage.  Cut bandage about 1/2" larger than damaged area.  Coat damaged area of speaker with rubber cement.  Carefully press tissue paper onto damaged area, insure there are no wrinkles or air gaps, or air bubbles.  Let dry for 24 hours.  Recoat top of bandage with rubber cement.  Let dry for 24 hours.  Insure that the damaged area is now about the same "stiffness" as the rest of the cone.  If it feels too flexible or wimpy still, you can repeat the process on the back of the speaker.