Looking for good Sound Proofing Insulation

[Hammie]

I've always read that tightly packed insulation and two layers of drywall will provide pretty good sound isolation. Keep in mind though, when you pack insulation too tight, it looses all insulating qualities and may no longer keep a room cool or warm adequately.

A quick Google search brought up a few pages, but after skimming some of them, this looked like a good one:

http://www.ehow.com/how_15992_soundproof-room.html