Posted by Rick Denney on September 08, 2000 at 13:36:58:
In Reply to: Re: More on Soundproofing... posted by Ed on September 07, 2000 at 22:47:53:
I haven't seen the stuff in person, but I'm guessing that it is a bit like the shock-damping stuff in running shoes, only softer. Some sort of expanded polyethylene. Sorbothane, perhaps.
The important characteristic is not how soft or hard it is, but how much hysteresis it has. Butyle rubber and latex rubber seem about the same consistency and look the same, but butyl rubber has much more hysteresis, and is therefore quite plastic. Latex is highly elastic.
The main thing they are doing with this stuff is to keep the two sheets of wallboard from sympathetically vibrating. The foam material in between couples them enough so they can't vibrate independently, but not so much that they vibrate as a single sheet. I would think a loose felt might work well enough, or perhaps a squishy foam weatherstrip.
Rick "not liking the screw attachements they used, however" Denney