Here is a post I wrote over at AM on how to makel your own low cost bass traps. Hopefully some fellers over here can get some useful info out of this post as well.
Make your own bass traps.
Hey Bubba, Thanks for the link and the time taken to write up that article. It’s just what I need for my “near-future” studio in my garage.
I printed it out and was going to thank you for designing the article to be able to print correctly in portrait mode. But I just noticed that everything wrapped correctly until just below the hooks and anchor picture. From then on, the text does not wrap and gets cut off. Any chance at changing that so that it wraps correctly? Much appreciated.
Paul
Hi Bubba:
That’s a nice report and a nice looking project … as well…
Bill…
Excellent!
No sense in spending hundred$ or thousand$ on simple projects like this…
I don’t have much control over the word wrap. Notice in the upper right hand corner there is an options box. Set that to “Printer friendly” view (Or whatever it is called) and it should look okay. I am a flipping admin on that board and I am not bright enough to figure out how to edit some of the typos on that thread. Ugh. It gives me a permission denied error. Eh, I’ll crack open the MySQL when I am back at work and do some more clean up.
As for cost if any one is curious… There is about $6 in hardware, $1 in wood, $5 in fabric, and $16 in insulation for each 4" trap. The spray adhesive is about $10 per can and will do roughly 6-8 traps. So they are dirt cheap when you compare them to commercial products and they work just as well.
Sorry Bubba, I didn’t even see the Options pulldown. The print option is all I needed. Thanks for pointing that out - and giving the prices. Now if you could put “Free Time” on that pulldown I’d be all set 
Paul
Thanks Bubba.
Nice write-up Bubba…thanks for posting!
Great post, Bubba! A keeper for sure.
Tip: In corners, stuff the space behind the trap with fiberglass insulation or acoustic foam. As Bubba mentioned, optimum is only stuffing it half way, so you can just use one layer of insulation behind a panel – no need to stuff the whole cavity unless that’s just the easiest way with the material you have.
I would suggest using a thin poly barrier around all the fiberglass or mineral wool but underneath the fabric to provide additional containment of the fibers. This will not affect bass absorbtion but may help avoid particulates floating around the room.
Jim