Treating Foam Surrounds

[Guest SteveG]

Someone on EBay is listing a pair of 3a's and raves about some latex material he applies to his foam surrounds. He says it is called "Jiffytex" and can be bought at flooring supply stores. Does anyone have experience with this or other treatments for foam surrounds? Do they work well at preserving? But do the significantly affect speaker performance? Are they advisable for new or recently refoamed speakers????

Here is the link to the seller

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...item=1338566110

Hope someone has experience with this.

[Guest]

Not a good idea.

#1, new surrounds made today will last 30-40 years, and there isn't anything you can apply to them that will make them last much longer without negatively impacting their performance. Old rotten surrounds are no different than a piece of rotten wood, you need to replace it rather than trying to save it.

#2, Anything that soaks into a foam surround "like a sponge" is going to stiffen it up and dramatically change its compliance. The stiffness of a correct foam surround is carefully calibrated to give optimal performance, and if you go and saturate it with something its properties are going to change.

#3, If this stuff is really water based, it wouldn't soak into a foam surround very well. It has to have some solvent content else it would just form a skin on the surface. Depending on what that solvent is, it may wind up shortening the lifespan of the foam.

#4, Plain latex compounds have lifespans ranging from a year or two out to maybe 10-15 years, less than the surrounds they would supposedly protect [think of those old rubber bands in your desk drawer].

The latex coating used in the speaker industry is butyl latex, and will retain its physical properties for about 50 years. You won't get a quality butyl latex from a carpet or hardware store, at about $150/gallon its too expensive to be swabbing on floors. Lucking you only need about an ounce or two to coat most any size [paper] speaker cone or cloth surround.

A thin coating of a true water based latex on a foam surround will have no ill effects at all, but then it won't really do any good either. Cloth surrounds do often need to be re-coated, as they depend on the coating material to make them airtight and provide a portion of their compliance. A thin coating on a paper cone adds little mass but does a good job at stabilizing the paper itself. The weight of an untreated paper cone can swing up and down about 30% based on relative humidity, and many wet/dry cycles over the years can eventually cause a paper cone to warp.

[Guest]

Dear SLT,

I am trying to re-coat the cloth surround on my AR-4Xs. I can see the cloth was coated with a black material but has fallen off over time while some remained. The colth surround needs to be sealed to prevent air leak or I may lose bass, am I correct? Where can I obtain butyl latex you mentioned? I have a pair of Marantz model 7 speakers and the 12" woofer has cloth surround coated with a soft black material and the surround seems to last forever, while the foam surround on the 4" mid rotted out long time ago and I had them re-foamed. Could this black material on 12" surround be the butyl latex you mentioned? I also have a pair of AR-2ax with cloth surround and I would like to coat them too. Them seem to have been coated with something originally.