I was thinking about using that neoprene pond liner they sell at home depot as a rubber mat, but I read on wetwebmedia that neoprene mousepads (the really spongy thick ones) work great. I think I have about 40 thousand of them laying around the house somewhere. (Tragic side effect of being in IT, and I don't even use a mouse pad with my optical mouse! )

Richard, thanks, Jim, the stuff I am thinking of lining the stands with is a studio quality sound absorber that a friend used to create an in-home stufio. I may line the inside of the stand with cork like richard did, and then lay the sound absorbinb material ontop of it. Denisty matters for sure, but I think it also matters WHAT material your using, obviously water is incredibly dense, and it translates sound across hundreds of miles (such as whale song). I would, and I think others, would DEFINATELY want to hear what you have to say aobut your techniqes, every little bit will help!!!!