New surrounds question

[rebuy]

I know a lot of folks have to replace foam surrounds. When doing this can you and should you try rubber instead of foam for longevity? Since rubber, IMHO is a better material, maybe this could be used with out degrading the original driver, just wondering.

[Schurkey]

Different surrounds can change the mechanical properties of the driver, for example the resonant frequency. Be careful.

The drivers in my Polk speakers are rubber. What Polk speakers use foam surrounds?

[Lasareath]

The drivers in my Polk speakers are rubber. What Polk speakers use foam surrounds?

Some really old ones did, from 1978 and back. Like the mini monitors which are currently being discussed in another thread.

[geoff727]

What Schurkey said x 2. Resonant frequency, resonant Q, equivalent volume of compliance, moving mass, SPL (sensitivity) of the driver, all can change. And if they change enough, it can 'throw off' the crossover, or cabinet tuning, or final cabinet resonant Q, etc., etc. Here's the tough part...how do you know what's going to change, and to what magnitude, until you try it and measure the before and after properties of the driver? That's the rub.

FWIW, I've redone a number of foam surrounds with butyl surrounds. On some, the drivers' properties changed. On others, they stayed close enough to almost be considered 'within factory tolerance' of normal driver measurements. Keep in mind, too, that most of the foam surrounds that are produced today are a far cry from that of years ago, and will age much, much better.

G~