Treatment for rubber speaker surrounds?


Anyone use any type of treatment like silicone for their speaker surrounds to preserve them from getting hard and drying out. Does any company make a product meant for this purpose? I have heard of people using Armor All but IMO that is not the best choice because it also can cause drying and cracking.
arnold_h

Showing 3 responses by nsgarch

Alright, enough frivolity!! Surrounds come in two basic materials (not counting the really early rubber-impregnated cloth and the corrugated paper types):

1.) Closed-cell, expanded polystyrene foam -- very common, but an older technology, and
2.) Neoprene rubber

What destroyed the first kind was primarily chemicals in (urban) air -- hydrocarbons, ozone, but also UV rays, especially in automotive installations. For years, there was a huge cottage industry that repaired deteriorated foam surrounds (primarily Altecs and JBL's) This material has been much improved and is still in use in less expensive transducers. A good practice with these is to gently wipe them occasionally with a dampened piece of turkish towelling and then spray a little automotive aerosol silicon onto another piece of dampened turkish towelling and wipe the surrounds (and cones if they're not paper.) I've been doing this for years with no ill effect.

The second kind is more resilient; and more resistant to contaminants and UV. 35 years ago it was a relatively expensive material. It became popular at first in long-throw woofers when foam just wouldn't hold its shape in the large widths needed to make long-throw cones. And the price came down when automotive tire makers began using it to combat the cracking in rubber tires due to increasing smog! It also has better mechanical damping characteristics and better sealing for acoustic suspension design. With zero care, it will eventually stiffen up, but it does take a few years. The cleaning/treating method I described above done every two or three years will definitely extend their life and make them look pretty too.

Nix on the ArmorAll -- Elizabeth is right about the petrochemicals -- which are particularly hard on most neoprene adhesives; whereas silicone is a natural component of neoprene rubber and vinyl. I think it must be the "active" ingredient in Last Record Preservative -- just WAY "watered-down"!
Eldartford -- OK, you win the frivolity run-offs!
And I agree, there's nothing wrong with the older designs. In fact a lot of dome tweeters simply mold the dome and "surround" out of the same material for exactly the reasons you mention.

The problem with foam is it's not very resistant to the elements. It's fine when protected. for example, when you remove a speaker from the cabinet, the foam compression gasket is always in good shape. I have a friend in Hawaii who had to replace the foam surrounds on his JBL's every 30 months on a regular basis. They just rotted away in the heat and humidity!
I hope I didn't imply that one should get anything wet. A barely damp piece of towelling with some nap is all you need to remove dust, and will not harm paper cones. It doesn't hurt to blow them off first with compressed air like DustOff. Sometimes that's enough. Just make sure you keep the nozzle at least a foot away.