Scan Speak Revelator Adhesive Failure - diyAudio
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Old 1st February 2014, 07:22 PM   #1
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Default Scan Speak Revelator Adhesive Failure

I'm working on a pair of Sonus Faber Cremonas and thought one of the midrange drivers, Scan Speak 15W Revelator, was blown because of the kazoo type sound it was making, especially audible on piano. When I pulled the driver the exposed portion of the voicecoil looked fine and there was no rubbing. I ran a 440 tone through it and it soon became apparent that the glue holding one of the cone slits together had failed, and that the slit itself was buzzing. The surround was also starting to become unglued at a point connected to the slit opening. I repaired the problem with adhesive and the driver works fine now. I decided to test the "good" speaker as well and found it to be bad as well, with the identical failure mode, although not as far along or audible as the first driver.

The speakers are around ten years old and have been used in a house at fairly extreme elevation, around 9,000 feet, so the low humidity that comes with high elevation might be a factor, but I really think this constitutes a pretty major design flaw. Drivers shouldn't just fall apart after ten years, even poly foam lasts longer than that. The woofers use the same technology, so I wonder when they will start falling apart. Sonus Faber wont help me on this as they are way beyond warranty, and of course "this is the first they've heard of it."

Last edited by audiomagnate; 1st February 2014 at 07:29 PM.
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Old 1st February 2014, 08:44 PM   #2
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Have you contacted SS?
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Old 2nd February 2014, 04:56 AM   #3
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Originally Posted by speakerdoctor View Post
Have you contacted SS?
I will try on Monday. Here's what's happening:Click the image to open in full size.
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Old 2nd February 2014, 12:17 PM   #4
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I've got a pair of 15W Revelators in my 'Intimates' speakers so have a keen interest in your situation. Mine are only 2 yrs old though.

It looks to me like you have a couple of repair options (assuming things with SS don't work out). Find some moderate viscosity black rubber cement you can dispense with a fine tipped applicator and re-seal that exposed section of the slit. You'll also be able to use that stuff to re-seal any portion of the rubber surround as well. Maybe SS will sell you a small applicator bottle of exactly what they use.
The other option is to cut a small patch if light weight porous fabric (scrim?) and glue it to the back side of the cone whilst pushing up on the seam to close it up to it's original width.
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Last edited by speakerdoctor; 2nd February 2014 at 12:21 PM.
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Old 3rd February 2014, 11:05 PM   #5
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No response from Scan Speak.
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Old 3rd February 2014, 11:13 PM   #6
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Quote:
Originally Posted by audiomagnate View Post
I will try on Monday. Here's what's happening:
From the photo can't tell the material of degraded rib.

I have found the out gassing of some synthetic carpet can turn certain plastics to mush (the belts used in turntables and tape machines), do you have any synthetic carpets or other plastics in proximity to the speakers?
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Old 4th February 2014, 09:36 AM   #7
Eric J is offline Eric J  United States
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The small waves along the surround edge suggest there's some expansion and/or contraction occurring there. That could be what's causing the edge of the cone slits to fail.

Maybe the dry air has caused the edge adhesive to shrink, or something had been applied to the surround that's caused it to swell. Some rubber conditioners and cleaners can do this to woofer surrounds.
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Old 4th February 2014, 05:14 PM   #8
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Originally Posted by weltersys View Post
From the photo can't tell the material of degraded rib.

I have found the out gassing of some synthetic carpet can turn certain plastics to mush (the belts used in turntables and tape machines), do you have any synthetic carpets or other plastics in proximity to the speakers?
The air couldn't be purer than where these have been, and there is nothing like what you are describing in the home.

Quote:
Originally Posted by Eric J View Post
The small waves along the surround edge suggest there's some expansion and/or contraction occurring there. That could be what's causing the edge of the cone slits to fail.

Maybe the dry air has caused the edge adhesive to shrink, or something had been applied to the surround that's caused it to swell. Some rubber conditioners and cleaners can do this to woofer surrounds.
Nothing has been applied to the surrounds.

I still haven't heard back from Scan-Speak. I don't speak Danish, and when I call all I get is a nice music loop and a message in Danish that keeps just repeating itself. Customer service sure isn't what it used to be in the luxury goods market.
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Old 4th February 2014, 05:21 PM   #9
tinitus is offline tinitus  Europe
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Originally Posted by Eric J View Post
The small waves along the surround edge ...
I noticed that too

also the slit 'glue' appear different from the 5" I once had
but maybe they changed it later
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Old 4th February 2014, 08:31 PM   #10
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These are around eight our nine years old.
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