Aside from all the other suggestions except the one about damping compounds as this is in line with that. But waaaay better. Considering all of the audiophiles on site, I'm somewhat surprised no one has mentioned using better quality damping materials. Specifically Navcom & Sorbothane.
They are the number 1 & 2 most effective damping materials available (and I'd recommend Sorbothane which is the cheaper of the two), and yeah...they cost. Alot. If your truly interested in quiet, constrained layers drastically increase the effective damping.
Constained layers meaning: one layer of Sorbothane. Another layer of say...Ear TAD damping foil, and so on. You get the idea, I'm sure
And yes, damping compounds do help with sound control. Sound is vibration.Edited by Lucky 13 SpeedShop - 4/26/11 at 8:55pm