Need Bass Trap design for 125Hz

[windpainter]

Hello!
I am excited about finging this forum and the wealth of information and ideas. I have been composing, performing and writing original songs and music for many years and have a pretty fine little studio with one problem;
a serious bass bump at 125Hz. The control room has been EQed with a pink noise generator, and both left and fight EQ controls are pulled completely down at 125Hz.
I want to build bass traps that specifically address this frequency, but to be honest, I am no mathmetician and the various methods to calculate this are beyond my simple skills. I read the equations and my eyes cross. Hey, I'm a musician, recording engineer and a pretty good carpenter; a man has to know his limitations!

Anyway, here's the basic specs:

Room size: 13'4" x 11'6" ceiling 9' high

My monitors sit about 10' from the back wall, which is 11'6" wide.

I have only one clear corner that might be used for a trap, but a 2' trap would take up too much space, so I am considering traps angled from ceiling to back wall, perhaps the sides. I could also build traps on that back wall, depending on how deep is needed.

I have read most of the posts here about bass traps, but the wealth of information has got me abit boggled. My financial picture is limited (Could it have anything to do with my career choice?) so building is my only option. It would be an enormous help if you fellows would do the math for this ignorant picker and just tell me what to build, out of what materials.

With your help, I could then return to something I know about, carpentry and music!

Thanks,
Dan
in the Blue Ridge mountains

[Ethan Winer]

Dan,

> The control room has been EQed with a pink noise generator, and both left and fight EQ controls are pulled completely down at 125Hz. <

I'll tell you up front that you're heading in the wrong direction. First, 1/3 octave analysis is way too coarse to measure the true response of your room. I assure you that in a room that size there are peaks and severe nulls all over the place. But you have to measure using at least 1 Hz resolution to see them. So you do not want bass traps that target one specific frequency. Rather, you want broadband absorption that handles the entire low end.

If you want to do this yourself, I suggest you get at least a dozen 703 or 705 rigid fiberglass panels - as thick as you can manage - and place them straddling the room corners. Not just the regular wall/wall corners, but also the wall/ceiling corners.

--Ethan

[dymaxian]

Hey Ethan, where's the link to that little video of yours?

Dan, as far as options go, there are lots of them. If you can build along the back wall, there's a bunch of absorbers you can put up there- look at the Wall Units page for an 8" deep, broadband absorber. We can calculate the exact dimensions for a panel trap that will absorb 125Hz, but Ethan's right- that might be the biggest of your rooms peaks, but it's probably not the only one. Strapping rigid fiberboard over all the ceiling-to-wall corners will probably do the most work for the least money.

Kase
www.minemusic.net

[Ethan Winer]

Kase,

> where's the link to that little video of yours? <

Go to my company's site www.realtraps.com and you'll see it listed at the top of any page under Acoustics Info. We have more videos in the works too. All just as home-made looking as this one.

--Ethan

[windpainter]

Hey!
and thanks for the replies. I'm slow but I do catch on eventually.
I did watch the video and my concept is expanding. Ethan, I really appreciate your input.

Kase, I have looked for a "Wall Units page for an 8" deep, broadband absorber" but haven't found it yet. Is there a specific section called
Wall Units Page? If not, then please direct me to the page you mention.

Another question: in reading through the various posts, I have read that any bass trap with board insulation less than 4 feet across will not flex enough to be effective. Is this so?
My space is small enough that I was considering smaller units so as not to overwhem the room, but I don't want to shoot myself in the foot either.
Dan

[Ethan Winer]

Dan,

> I have read that any bass trap with board insulation less than 4 feet across will not flex enough to be effective. Is this so? <

What type of bass trap? Wood panel? Rigid fiberglass? Wood panel traps do need to be large enough for the panel to flex. The ones I've built are two feet wide and between four and eight feet tall. That's a good size range, but understand you need a bunch of them to properly treat a room.

--Ethan

[knightfly]

http://www.johnlsayers.com/HR/index1.htm

scroll down close to the bottom for the wall absorber -

You can reach this and other really helpful resources by clicking on the John Sayers Productions logo at the top of these pages... Steve