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Redoped cloth surrounds

J

jbehr

New Member
I redoped the cloth surrounds on the woofers of my Wharfedale W90c's with watered down Aleene's tacky glue. My main reason was to prevent over excursion as these are acoustic suspension speakers. Once I got the woofers out where I could see them backlighted I found there was pretty much nothing there but a rather loose weave fabric, just a lot of square holes, no remnants of any old dope. Good thing I don't ever turn the volume up much.
In my reading of the info here I've seen reports of much better control (tightness) of the bass after redopeing. That makes perfect sense to me since if they aren't sealed they don't have that pillow of air to compress going in, or when going forward to stretch it (pulling a vacuum).
Now comes my question, I haven't really noticed better control of the bass, but there is a lot more of it. I have turned the bass tone control down from +2 to -2. to sound pretty much the same. Has anybody else noticed more bass volume after redopeing?
 
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jbehr said:
I redoped the cloth surrounds on the woofers of my Wharfedale W90c's with watered down Aleene's tacky glue. My main reason was to prevent over excursion as these are acoustic suspension speakers. Once I got the woofers out where I could see them backlighted I found there was pretty much nothing there but a rather loose weave fabric, just a lot of square holes, no remnants of any old dope. Good thing I don't ever turn the volume up much.
In my reading of the info here I've seen reports of much better control (tightness) of the bass after redopeing. That makes perfect sense to me since if they aren't sealed they don't have that pillow of air to compress going in, or when going forward to stretch it (pulling a vacuum).
Now comes my question, I haven't really noticed better control of the bass, but there is a lot more of it. I have turned the bass tone control down from +2 to -2. to sound pretty much the same. Has anybody else noticed more bass volume after redopeing?
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You raised the resonance point of your woofers by stiffening the surrounds somewhat, which can have the effect of increasing upper bass response at the probable expense of the lowest bass response. Hopefully you have achieved an acceptable balance for your listening preferences. Tacky glue is not the best way to seal acoustic suspension woofer surrounds, as it will also stiffen them.

Roy
 
RoyC said:
You raised the resonance point of your woofers by stiffening the surrounds somewhat, which can have the effect of increasing upper bass response at the probable expense of the lowest bass response. Hopefully you have achieved an acceptable balance for your listening preferences. Tacky glue is not the best way to seal acoustic suspension woofer surrounds, as it will also stiffen them.

Roy
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Wondering....

What are some of the alternatives to Arlenes ? I did a pair of AR4's and used Permatex High Tack. Although it seemed to work ok, I still have to believe there is a better product out there
 
perchdog said:
Wondering....

What are some of the alternatives to Arlenes ? I did a pair of AR4's and used Permatex High Tack. Although it seemed to work ok, I still have to believe there is a better product out there
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If there is a dedicated commercial product for the purpose of sealing an old cloth surround woofer without compromising compliance, I have not come across it. (This is a topic that has been discussed here and, over at the Classic Speaker Pages at length.) There are a number of options much better than tacky glue, however. It is great for gluing things like replacement foam surrounds, but will stiffen cloth surrounds when applied as a "sealant".

Permatex is a good option when thinned and used sparingly. I've made my own non-drying butyl compound. Others have used thinned rubber based materials with apparent success.

Roy
 
Thank you for your reply, Roy. If they've lost any low frequency ability it isn't apparent to my ears. I put on 3 very light coats with a half inch artist brush. Just tried to bridge the holes in the weave. I hope i didn't stiffen them up too much.
 
I have a pair of Wharfedale woofers that need a little love, and a pair of 12 in Celestas that really need sealing ,surrounds like gauze. What would one use to thin the Permatex? Not trying to jump the thread, just getting an idea of what the better solution would be more specifically.
 
I would also like to hear about other products one could use. I'm also curious about other people's results who have redoped theirs.
 
Permatex is butyl based, and can be thinned with toluene or lacquer thinner. Other materials such as rubber cement, which is a latex compound, can be thinned with heptane (both found in Michael's Craft Stores), and silicone rubber thinned with MEK (be careful with MEK, as it can un-glue your surround) will also work. My non-drying stuff is made from an industrial butyl compound (butylene) and toluene, similar to compounds used by AR, KLH, and Allison.

Various caulks have been mentioned in the past, but I've only measured one latex caulk. The results were not great....though it did measure better than tacky glue. The worst I have seen were surrounds coated with varnish!

Of course the forum is full of "success" stories, but unless some measurements are conducted there is really no way of knowing the actual affect on the speaker's response. Further, some materials will stiffen over a relatively short period of time.

Btw, my comments and experience pertain only to sealed (aka, "acoustic suspension") speaker systems, which are more likely to be compromised by woofer surrounds suffering from diminished compliance.

Roy
 
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Curious about Shoe Goo, that stays very flexible, almost to the point of being soft...but Im sureit would have to be thinned quite a bit, its quite thick out of the tube.
 
bobaloniny said:
Curious about Shoe Goo, that stays very flexible, almost to the point of being soft...but Im sureit would have to be thinned quite a bit, its quite thick out of the tube.
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Great adhesive, which can be thinned with toluene, but dries much too stiffly...

Roy
 
What about....

I've got a pair of Optimus 5 speakers that have cloth surrounds on the cone tweeters and mids. I've been told here that it is silk. The material is intact, but whatever they originally used to dope the surrounds is MIA. Would doping these surrounds with anything mentioned here raise the resonant point of these drivers enough to make a difference? I mean we're not talking long x-max woofers here.
Any thoughts?
 
I think that a thin layer of Ailenes would do little to stiffen the surround, and if it raises the resonance, it might return it to the original specification. The OP seems to have taken care to apply as little as possible, and over the entire roll of the surround, I doubt if it has much effect on the motion of the driver.
Just a guess, but my understanding is that the surround has much less control on the driver than the spider does -- it's much stiffer. And probably the spider is a little looser than it started out, so if the surround actually does get stiffer, that might not be a disaster. But I don't think it does.
 
Nat said:
Just a guess, but my understanding is that the surround has much less control on the driver than the spider does -- it's much stiffer. And probably the spider is a little looser than it started out, so if the surround actually does get stiffer, that might not be a disaster. But I don't think it does.
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The spider and surround comprise the entire suspension system. Stiffen either one, doesn't matter which, and compliance decreases. Some of the old surrounds have actually stiffened a bit due to the original treatment drying out. I do agree that spiders will loosen somewhat with time, however. It is just that it is never known what can be gotten away with. Measurements I have conducted of tacky glue treated AR and KLH surrounds show increases of fs and fc significantly beyond original specs.

I just wanted to throw some caution in the mix regarding the use of tacky glue for this purpose. The OP was careful, and seems satisfied with his results, so hopefully all is well.

Roy
 
RickeyM said:
I've got a pair of Optimus 5 speakers that have cloth surrounds on the cone tweeters and mids. I've been told here that it is silk. The material is intact, but whatever they originally used to dope the surrounds is MIA. Would doping these surrounds with anything mentioned here raise the resonant point of these drivers enough to make a difference? I mean we're not talking long x-max woofers here.
Any thoughts?
Click to expand...

It depends on the original purpose of the treatment. It is not likely it was used to "seal" the drivers in the cabinet, as with acoustic suspension woofers. Mids and tweeters have their own enclosures, and are not open to the inside of the cabinet. Adding anything to them could change important aspects of their response, and it is probably best to leave them as is. Are you sure anything was applied to the mids and tweeters in the first place? It is not typically necessary to re-treat any driver, especially mids and tweeters.

Roy
 
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Certainly careful modest treatment is crucial. I'd be curious about the tacky glue treatment of the woofers you measured -- was it a heavy coating, or was it a diluted thin painting?
 
Nat said:
Certainly careful modest treatment is crucial. I'd be curious about the tacky glue treatment of the woofers you measured -- was it a heavy coating, or was it a diluted thin painting?
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The woofers I measured had one thin coat of tacky glue. It does not take much to screw up compliance. It also became worse within a few weeks. If the membrane that is formed is stiff, regardless of thickness, the woofer loses compliance.

Just apply any of the materials mentioned in this thread next to each other on tissue paper. The differences between the rubber based compounds, and tacky glue are obvious...and very measurable when applied to a woofer.

Roy
 
That's good to know. Do you have any thoughts on using latex caulk (Alex, to be specific) as suggested by a couple of people in Speaker Builder (or was it Audio Xpress?). I think the method of application was spreading and scraping with something like a credit card to work it into the foam and remove excess. The same was done with butyl caulk -- I assume you'd think that would be more promising.
 
Nat said:
That's good to know. Do you have any thoughts on using latex caulk (Alex, to be specific) as suggested by a couple of people in Speaker Builder (or was it Audio Xpress?). I think the method of application was spreading and scraping with something like a credit card to work it into the foam and remove excess. The same was done with butyl caulk -- I assume you'd think that would be more promising.
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I measured one type of latex caulk early on, with so-so results. That is not to say other (diluted) rubberized caulks cannot work. Some folks have reported subjectively good results with caulk.

The key is the amount of rubber in the compound, and as previously discussed, thickness of application, number of coats, etc.... This is what initially led us to the Permatex material. It is butyl based and remains somewhat tacky, much like many of the original compounds. Even this material should be thinned, however. I've found it is the degree of drying or curing that compromises otherwise promising materials used for this purpose.

Roy
 
Not to drag up an old thread or anything...

I've tried a spray-on rubberized treatment called "Good-Bye Cracks" (Lowe's) for re-doping old fabric surrounds like AR. Its designed to spray over cracks in drywall of plaster so they can be painted over. It is a rubberized spray. That seemed to work pretty well and was easy to apply evenly by masking off the surround and just spraying it on. It just soaks into the fabric and dries soft and flexible, kind of a slate blue color. Appears to be perfect for these old fabric surrounds. Amazing how they just jump back into a nice curved shape after you spray this stuff on. IMHO this is the perfect solution. :yes:

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Since there are several of these threads floating around at the moment, maybe I should point out what it appears most of us are trying to do with glue on cones or surrounds.

We're not trying to "tweak" a perfectly good speaker. Rather, we are trying to take an older speaker that has detiorated and restore it to a "better" condition than it is presently is.

We're not trying to claim that these repairs will make the speaker be as good as new, or as good as a proper recone with a surround replacement. However, if done with care, perhaps we can get the speaker back to a level of performance that will be acceptable.

We're also dealing with the realities that sometimes replacement spiders, voice coils, cones or surrounds may not be available anymore, leaving a proper rebuild or recone to be impractical. And we may also be dealing with monetary constraints. So we're trying to take an approach that has some chance of success (and hopefully still being cost-effective).
 
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