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

powerjoe · Post by **powerjoe** » Wed Jul 20, 2005 7:24 am

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

knightfly · Post by **knightfly** » Wed Jul 20, 2005 2:01 pm

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

powerjoe · Post by **powerjoe** » Wed Jul 20, 2005 2:21 pm

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

knightfly · Post by **knightfly** » Wed Jul 20, 2005 7:03 pm

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...

powerjoe · Post by **powerjoe** » Thu Jul 21, 2005 12:06 am

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

knightfly · Post by **knightfly** » Thu Jul 21, 2005 5:20 am

Cool, that's hopefully the plan

Now, if you could (as stated in the link, in bold type )

Edit your profile to include your location.

Thanks...

powerjoe · Post by **powerjoe** » Thu Jul 21, 2005 5:42 am

knightfly wrote:Cool, that's hopefully the plan

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

knightfly · Post by **knightfly** » Thu Jul 21, 2005 8:25 pm