Any thoughts on Blown-in cellulose, it can also be sprayed-on. I was also thinking of filling the attic(over the garage) and existing walls with it. I can rent the blower and buy the 40 sq ft bags($5) anywhere in town(blown-in). I read on several sites that per inch, it is a little better than rockwool and much, much better than the pink stuff...........is this hype? If you remember I have a standard brick vineer home garage. brick\air gap\felt paper\5/8 shranboard\2x4 studs\3/8 drywall. All I have to do is cut small holes at the top of the wall to blow it in, very easy(helped do it before), then repair the drywall holes.
I also read http://www.saecollege.de/reference_material/index.htmlThe following Sound Transmission Class (STC) ratings demonstrate its effectiveness in attenuating noise. The higher the STC number, the greater the reduction in sound.
Cellulose insulated wall 44 STC
Fiberglass insulated wall 39 STC
Uninsulated wall 35 STC
[Ratings for the empty wall and the fiberglass insulated wall are from the Owens-Corning “Noise Control Design Guide”. Ratings for the cellulose insulated wall are from the Cellulose Insulation Manufacturers Association.]