So my brother is being a bit cheap now that he dropped 2800 on the stereo. I'm trying to find economical sound deadening materials. We got a bunch of Butyl aluminum backed vibration dampening. I've been trying to think of what to use for a closed cell foam barrier. Anyways after thinking a while it dawned on me to use laminate floor underlaying. They have some that is closed cell and about 1/8" thick. This is about the same thickness of the RAAMmat stuff but the price is very nice at 200sq ft for 60 bucks shipped. If I had to I could double it up for better sound barrier.
Laminate Wood Floor Green Underlayment Foam Pad 3mm - eBay (item 190298529419 end time May-03-09 11:44:51 PDT)
Laminate Wood Floor Green Underlayment Foam Pad 3mm - eBay (item 190298529419 end time May-03-09 11:44:51 PDT)