Treating Foam Speaker Surrounds?

[markd51]

I've thought of this for many long years, whether there might be benefit.

Of course 30 some years ago, there wasn't much on the market to use, except maybe something like Armor-All, which would likely not help and might even possibly accelerate degradation.

As I understand it, Ozone is the culprit of rotting Foam.

But today, there are much better protectants for vinyl-rubber, some now are water based, The auto detailing industry has many seemingly better products that might help stave off rotting I might believe.

I am aware and understand with no treatment, and with foam surrounds, it's surely only a matter of time, that all of them will rot and crumble at some point.

I'm also aware that it may be very difficult and even impossible to treat the backside of foam surrounds.
Still, I'm thinking there might be some advantage and merit.

 

[SiliconTi]

Naw, not worth the effort. The material itself just falls apart over time, nothing you can do about it.

 

[Nat]

I'm told that the foam used nowadays is longer lasting than earlier formulations. I'm not exactly convinced. But I've never found anything that I trusted to lengthen the lifespan of foam without also changing it's characteristics, hence the behavior of the driver.

 

[teal'c]

While ozone may or may not cause the foam to disintegrate, constant movement does.

 

[Nat]

Not disagreeing with you, but my experience has been that the speaker that sit for long periods seem to have more surround degradation than the ones that get used alot - that might be that the stored ones aren't in as climate controlled spaces as the ones in my living room. Which, of course, is a datum in itself.

 

[Harvestor]

https://www.simplyspeakers.com/speaker-repair-cone-edge-sealer-mi-1291fg.html

Our special formula Foam Guard PVA vinyl emulsion sealer is designed to extend the life of new foam edges by preventing moisture absorption, microbial attack, and UV damage. Dries clear and flexible. One bottle will treat 6 to 8 speaker surrounds. It is also used on professional speakers to seal and treat fabric or cloth cone edge suspensions, and to seal and dampen paper edge cones.

 

[swechsler]

I'm told that the foam used nowadays is longer lasting than earlier formulations. I'm not exactly convinced. But I've never found anything that I trusted to lengthen the lifespan of foam without also changing it's characteristics, hence the behavior of the driver.

I don't know if this is necessarily true; I think it depends on the speaker. For example, I own both Infinity Kappa 6.1s and 8.1s, built around the same time. The 6.1s surrounds turned to dust a few years ago, but the 8.1s are still going strong (even though both sets are in the same room). Now, they were all purchased second hand, so I don't for sure know how they were treated before I got them, but I also own a second pair of 6.1s and a few Kappa centers, all from around the same time. The 8.1s are the only ones whose surrounds haven't rotted, and the foam looks different than the foam on the others (it's a much darker grey, almost black, compared to the standard grey of the others).

 

[bimasta]

I'm told that the foam used nowadays is longer lasting than earlier formulations. I'm not exactly convinced.

I was told the same, but I am convinced: it ain't true. Bought some new 6.5"s made by a prominent company 7-8 years ago. They're dust now. The "bad" old ones lasted twice as long.

 

[RTally]

This topic comes up every so often. The general thinking is that the surrounds are designed a specific way so that the driver has specific characteristics. That is why those with cloth surrounds are very particular about doping the surrounds. They use only the special material developed by RayC and apply it sparingly so as not to change the driver characteristics by adding mass to the surrounds and increasing its stiffness.

The same applies to foam surrounds. When replacing foam surrounds, we want the replacement foam to match the factory foam as closely as possible. We want to use the same style of surround, for example, the correct flat, double-sided type or the Boston-style direct attach edge. We want to attach it the same way, for example, to the front or back of the cone. We do not want to add mass to the cone by using too much glue so we use only enough adhesive to securely attach the foam surround to the cone. Attaching the surround to the basket lip is different. Feel free to slather it on when glueing the foam to the basket lip.

Adding a coating or sealant to the foam itself will change the compliance and other characteristics of the foam. Any coating or treatment will add mass to the surround and likely affect its stiffness or flexibility. I don't care that a popular speaker parts firm sells sealer (which is nothing other than white PVA glue) that can be applied to foam. He is not the one who has to listen to the speakers. And they have not provided test data that shows that the driver characteristics are not changed by using the sealer.