foam/rubber/cloth or mystery materail

[SEAWOLF97]

SERIOUS QUESTION:

I have never seen this Q fully answered....

When the designer sits down to develop a new driver , what criteria does he use to determine what type of surround material to use ?

foam ?
rubber ?
doped cloth ?
mystery material (as in my L56's) ?

is it price ? some performance idea ? production time ? longevity ? etc...:)

[Robh3606]

That's an interesting question. The obvious answer is what works best for that driver and application. How they are selected is hinted at here:

http://www.lansingheritage.org/images/jbl/reference/notes/tech1-3a/page06.jpg

Rob:)

[Mr. Widget]

That link only covered the types of surrounds then in use by JBL Pro.

As for the foam vs. butyl rubber surround choice, I was told that foam is lighter and adds less effective moving mass to the woofer. Also foam and rubber damp out cone edge resonances differently. I am sure some woofers could be designed to work equally well with either foam or rubber.


Widget

[JBL 4645]

I’m for rubber on smaller speakers and cloth ribbon on large speakers.

The JBL 2240 has been durable over the 11 years well maybe 13 years since I brought off one owner.

I wonder if they make small rubber surrounds to fit control 1?

Why is it that JBL fits its newer speakers with rubber and not its older ones.

Foam is depressing after all the stories I’ve read. (Its bad to live near the ocean the salt-air will rot the surrounds). Stuff like that just sends me into a downer.:(