Bare insulation as broadband absorbtion?

michael collinge · Post by **michael collinge** » Fri Oct 20, 2006 12:04 pm

Hey guys, please excuse the newbie question.... I tried using the search function...

I am turning an old garage into a little studio space. The space is probably about 25 x 15 with a gable ceiling.

Right now the room is far too reflective, so I am considering different options for broadband room treatment. I know, of course, of the use of rigid fiberglass insulation for this purpose. But how about regular pink insulation?.

Since the garage is uninsulated right now, I thought that maybe I could: insulate the room like normal, but rather than covering all of the insulation with poly and then drywall, cover some with a fire-retardant cloth instead. I could also leave the "bare" insulation at intervals in the room so as to minimize parallel surfaces of drywall. Like, maybe leave 40 or 50% bare.

Will this result in a room that is too dead?

Keep in mind that this is a low budget option (less that $500), not an ideal scenario.

Thoughts?

Michael Collinge

knightfly · Post by **knightfly** » Sat Oct 21, 2006 7:06 am

Standard fiberglass insulation is typically about 0.8 PCF so would require several FEET of thickness to come close to the absorption (at most frequencies) that the rigid stuff (typically 3 PCF and up) will get. Covering most/all your surfaces with this will result in a very boxy, boomy room similar to using carpet.

For a better grasp on some of this, go here

http://www.saecollege.de/reference_material/index.html

and specifically click on the links for acoustics, absorbers, reverb calculator (and any others that may intrigue you) - however, do NOT use the helmholtz calculator there or anywhere else; the one in THIS forum has been corrected to the proper formula.

HTH... Steve

michael collinge · Post by **michael collinge** » Sun Oct 22, 2006 3:54 pm

Excellent answer. That is exactly the information I was seeking. Thank you!

z60611 · Post by **z60611** » Sun Oct 22, 2006 5:21 pm

701, plain 2" (51mm) on wall 1.5 pcf (24 kg/m3) 0.22 0.67 0.98 1.02 0.98 1.00 0.90

Unfaced 2.5" R8 on wall 0.21 0.62 0.93 0.92 0.91 1.03 0.85

703, plain 4" (102mm) on wall 3.0 pcf (48 kg/m3) 0.84 1.24 1.24 1.08 1.00 0.97 1.15

Unfaced 3.5" R11 16" air 0.80 0.98 1.01 1.04 0.98 1.15 1.00