Originally Posted by avare
The first factor is the available depth. For absorbers ~4" thick 703 like materials are just about ideal. For deeper absorbers, up to ~12", 4" of 70s 703 like material with the balance being an air gap, is great. Mineral and glass insulation of the R30 thickness and density is in the same class at thicknesses of ~8" and up. The deciding factors should include: ease of handling during construction, any additional mechanical support for softer material, surface durabiolity, and of course, cost.
This is really the exact information I've been looking for, but I'd like to ask a more specific question, covered in my very lengthy first post in my recent thread, "Please Help pick correct insulation for my SuperChunk Build & Placing GIK 244 Panels" that hasn't, as of yet, provided a specific response to this question.
I have a large room, for HT use, at 20.4' x 26.66' x 8.66' wlh.
My front/screen wall is a poured concrete foundation (room is in basement) and my actual screen and front "wall" (nothing more than black thin curtains covering the width of the room to the left and right of the centered screen) is exactly 12" in front of the actual concrete wall.
This leaves me a 12" gap.
I was thinking of using this product, available from my local Lowe's, called, "Johns Manville 300"L x 15"W x 9-1/4"D R-30 Fiberglass Insulation Roll" at only $15.87 per roll.
I cannot find any specific gfr #'s/info on it though.
My plan is to use one layer, 9.25" deep, hung vertically from the ceiling to the floor, all across the entire width of the room (it's unfaced) at 20.4'.
In addition, I was thinking of making corner traps out of this, too.
I have the room to do 15" (the width of this stuff) x 18.5" (2 layers deep) which would simply be two pieces, hung vertically from the ceiling to the floor, so as not to have to use any netting or shelf support as it won't be able to compress on itself this way.
I could also pretty easily use four pieces, making a 30" x 18.5" rectangle trap, again, each of the four pieces hung vertically and this would be extremely cheap and easy.
The Question is, would using this material, in this configuration, be "effective?"
Would either/both sizes be as effective (looking for broadband bass absorption, don't care what it does to the highs since this is just for corners and room is so big) the way I plan to "hang" them as using Roxul or OC703 and building SuperChunks with a 34" face, triangles in corner?
That is what I really need to know. I've read about 200 threads over the last few weeks and just cannot seem to get a feel for whether this is a good idea.
I find it strange that I would be the first one to come up with this extremely simple and cheap way of making these, so I've been assuming it's probably just not an effective bass trap, but I'd like to call on your expertise and ask your direct opinion.
Thanks so much for all you offer here!