I think I can get some of the 80# Roxul stuff from Grainger.
Another question, for the purpose of sound insulation so I don't hear HVAC noise and don't bug my wife, can I just insulate 2 walls in the HT room? Or is it all 4 walls or bust?
This is a diagram of the basement where my HT is located. I want to insulate the Front and Back walls to both lower the noise floor and not bug my wife at night. (The wall behind the 2' counter is concrete blocks.)
Part of the appeal of sound-proofing the front and back wall is because they're unfinished and the studs are exposed. So I was thinking of putting in some sound isolation batts and then a sheet of MLV.
From my understanding, I could even leave the MLV exposed, since it faces unfinished portions of the basement where asthetics isn't that important. And by leaving them exposed (without another layer of drywall sandwiching them), the performance shouldn't be effected?