Comprible to 703?

[David French]

Tony,

You can't directly compare published absorption specs to performance in a small room, because those specs were recorded in a reverberation chamber. In a reverberation chamber, sound stikes the test material from random direction, but in a small room in the modal region, sound is striking the material from only one direction. In my experience, 2" 703 across the corners is effective on modes above 100 Hz; below that, its effectiveness falls off sharply.

[tonocus]

Thanks, that's exactly what I needed to know. Since one 2" layer isn't enough, I think I'm going to do two layers of 2" Roxul RHF 40 with roughly 8" of air space in between. It's for a rehearsal room that is: 20.8'L X 10.6W X 6.7'H.
I just want to tame the sound a bit since it will be hard to hear everything clearly. I'm putting in an order for two bundles of 10 2'X4'X2" panels, 6 of them going towards the bass traps, and the other 14 going on the walls with 2" spacers so they are not directly touching the drywall.

Thanks,

Tony

[AVare]

I think I'm going to do two layers of 2" Roxul RHF 40 with roughly 8" of air space in between.

Forget the space in between. Put both layers together.

Andre

[relaxo]

forget any "space" (air space) at all stuff it with any insulation, mineral wool, fluffy pink, 703 scraps, etc