What kind of Fabric is NOT good for Bass Traps /absorbers?

Hey there, I am on a super limited budget for bass traps. I was going to buy some "seconds" from a baa Trap manufacturer, and even though the gentleman there was extremely helpful and kind, I just can't afford the price. So, I am going to have a family member make some of the bass absorbers on his own. The thing I really need to know it, what covering materials are good, and ARE NOT good for this application? Is polyester okay? How about wool? I understand Burlap is good, but will that allow the insulation or rockwool fibers to escape through their weave? Can I cover the insulation or rockwool with a plastic bag and then use burlap? Any advice on coverings would be great. I love the look of polyester, but am not sure about how it will handle sound. Thank you so much! Joel

For lower frequencies, the type of covering isn't as critical - so use your polyester, even wrap the batts in garbage bags first, no problem; all that will happen is you'll keep a bit more of the highs in the room... Steve

knightfly wrote:

For lower frequencies, the type of covering isn't as critical - so use your polyester, even wrap the batts in garbage bags first, no problem; all that will happen is you'll keep a bit more of the highs in the room... Steve

Thank you SO much! So, will I still be able to capture the "really" low, lows if I use the thin plastic bag, and polyester? Is tight weave burlap and no bag much better all around? Thanks again! Joel

No, using absorbent across the room corners will get you down to maybe 200 hZ or so; but for best absorption the absorbent needs to be 1/4 wavelength of the sound being trapped as the distance away from the wall; the 1/4 wavelength of 30 hZ is nearly 9 FEET, so for this low a frequencies you need panel traps, which work on a totally different principle than absorbent traps. Bridging the room corners will smooth out most of the room modes, positioning of your head and speakers (in all 3 axes) will help (should be done first) and if your room has serious modal problems (wrong ratios of width to length to height) then you may need to consider a few panel traps to smooth out those particular lower frequencies... Steve BTW, did you read the announcement at the top of the forum? Please do...

Holy crap! I did not read that announcement and am sorry for not taking the time to do so initially. Wow, there is a lot of reading/ information there. Thank you so much Steve. I apologize for not having my wits about me when posting and reviewing this forum. I initially posted here: http://www.johnlsayers.com/phpBB2/viewt ... ght=#27304 and made note of some of the measurements of my room. There are some photos there too. Thanks again Steve. You are REALLY helping me. Joel

Cool, that's hopefully the plan :wink: Now, if you could (as stated in the link, in bold type ) Edit your profile to include your location. Thanks...

knightfly wrote:

Cool, that's hopefully the plan :wink: Now, if you could (as stated in the link, in bold type ) Edit your profile to include your location. Thanks...

Okay, sorry about that. I updated my profile to show my location in Minneapolis, MN