I was reading through Ethan Winer's "Acoustic Treatmen and Design for Recording Studios and Listening Rooms" -

http://www.ethanwiner.com/acoustics.html#top

and came across the following quote:

"Another great and inexpensive way to make a bass trap - if you have a lot of room - is to place bales of rolled up fluffy fiberglass in the room corners. These bales are not expensive, and they can be stacked to fill very large spaces. Better still, they are commonly available and you don't even have to unpack them! Just leave the bales rolled up in their original plastic wrappers, and stuff them in and near the room corners wherever they'll fit. Stack them all the way up to the ceiling for the most absorption."

I am not doubting this, just wanted to know if anybody has tried this method. My speakers and sub will have a GOM/speaker fabric wall in front of them and I think I can easily hide a roll of fiberglass. That just seems way to easy!!!! I will also be using my soffits and riser as bass traps, so this won't be my only bass trap.

Thanks,
Matt

Sure, that works. You might want to try to figure out the density of the compressed bales of the fluffy stuff. You could also just get a bale of fiberboard and do a similar thing. However, it might be worth pointing out it isn't the most efficient use of the fiberglass. If you buy the fluffy stuff, you have to leave it in the bale all compressed otherwise when it expands it's not really useful for anything because it's not very dense at all. With fiberboard you can use the boards in various locations and get better use of them. For instance, I have a bale of fiberglass boards in the corner for a while before I got around to building corner traps. I then used the boards to go floor to ceiling in two rear corners straddling the corner. It's like 6-8 inches thick if I recall, hollow behind, but the overall effect is much better than just leaving that stuff packed up in the corner. So while the bale in the corner may be effective and a lazy route to go, it may not be the most effective/efficient overall. But if you already have bales of fluffy stuff laying around that you're not using, sure absolutely it's a fine idea to use that as long as it's all compressed and dense enough.

Would bags of blown in cellulose work as well? Those seem to be fairly dense.

Bpape helped me with my bass trap design and recommended 2" 703 cut into triangles and then stacked on top of each other. I would think that 703 board would be denser than just a bale of fiberglass compressed, so maybe it is just a matter of losing too much space to go the compressed fiberglass route. You absolutely need mass to trap bass frequencies. The traps from Bpapes design take up 17"x17" of wall space with a 24" face. I plan to leave my baseboard trim 18.5" off the corner to allow for the fabric track.

How about a roll of Linacoustic. Substitute some straps instead of the plastic, wrap in fabric and you are done. We get the rolls for $125 in the DC area.
http://i23.photobucket.com/albums/b393/bigmouthindc/DSCN3356.jpg

Sure, that works. You might want to try to figure out the density of the compressed bales of the fluffy stuff.
Let's see. R11 is 3 1/2" "uncompressed. The radius of the circular bale of fiberglass is r. The number of linear feet in the roll is ...

Aaah, forget it! :)

- Terry

Sure - it'll work decently. But you can do a whole floor to ceiling solid chunk of 703 for less than $100. 2 Bales of Linacoustic for $250 may be easier but certainly not cheaper.

Bryan,

We've been visiting about using Ultra Touch for the bass trap. What are the advantages of using the Ultra Touch for a corner bass trap vs. the OC 703? The 703 seems to be a cheaper option.

Thanks,
Matt

Well, the 703 is a little more expensive but it's easier to cut. It's really a matter of what you need. Either will work very well when done as a solid absorber.

Bryan

and just to add, you could also use 4 pound mineral wool to stack floor to ceiling. That is cheaper then either. Kind of hard to work with though.

Glenn