Foam vs. Rubber Driver Edge

[bandit]

I wonder what your opinions are on foam vs. rubber driver surrounds? (the part that connects the outside edge of the cone to the driver frame) I've had some higher line older JBL speakers that this foam has rotted away on for the woofers. I was able to repair it, but I think that rubber is less likely to have this issue. The reason I asked this in the sub Forum is because I notice that the AV-123 MFW-15 seems to have what looks like the foam surround vs. rubber.(MFW-15 is a very nice looking product) Maybe the technology has improved on the foam surrounds since my older JBL's were made?

Bandit

 

[C.A.P]

New foam technology is way better . Its a matter of driver specs that they have to use foam or rubber as rubber is heavier and may lead to poor Thiel Small specs for that driver. Its lighter and will give a much different design parameters.

 

[annunaki]

Newer foam materials are much more resistant to dry rot. They will last substantially longer than previous iterations. Butyl, NBR, Santoprene, and other synthetic rubber surrounds will essentially last forever, but can break down some in terms of resiliency but not to the point one should be concerned. The reason foam is still a preferred material is that it has excellent resiliency and it does not "pucker" under high excursion scenarios. Great care must be taken when designing a driver with a rubber surround so as to prevent the surround from "puckering". "Puckering" can cause non-linearities under high excursion scenarios and unwanted audible noise. Pliability used to be an issue with rubber surrounds as well but has become more of a non-issue with all of the different types of synthetic rubber available.

Most drivers now days are fairly well designed and do not suffer from "puckering" issues. The same goes for foam surrounded drivers as they are treated and will last for quite a long time.

 

[bandit]

Thanks guys, I'd never heard anyone discuss it and I was curious. It all makes sense.

Bandit.