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Huge bass absorbing wedge #1


damonrpayne

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48" tall. I thought the bass was punchier in some of the songs I know extremely well, but I'm chalking this up to psychological expectation until I get around to measuring. I intend on building another one for the other side. I have a down firing sub so hopefully I'm not just robbing myself of corner loading in that case...

post-12530-13819411018192_thumb.jpg

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48" tall. I thought the bass was punchier in some of the songs I know extremely well, but I'm chalking this up to psychological expectation until I get around to measuring. I intend on building another one for the other side. I have a down firing sub so hopefully I'm not just robbing myself of corner loading in that case...

Alright damon[Y]

If the bass absorbers are doing what they should you should notice more definition and punch without any sense of loss of bass from the sub or Pals and actually these should add clarity even into the lower vocal range.

I will say as you clean up the low end response of the room it is possible to have an especially problematic modal area begin to be heard more clearly and if that happens a sharply tuned bass trap can be used to help with it.

The room and Pals sure look good damon!

mike tn

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are those the Roxul triangles that you were cutting when Roger and I stopped by last year during our Green Bay road trip?

Can you show dimensions and how you arrived at those? Also, how did you cover/finish them off? Knowing you and your wife's fine tastes in decorating they had to be wrapped in some nice fabric or something.

M

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Right, these are made out of Roxaul Rockboard 60 which is a little more dense and cheaper than OC703. The come in 2' x 4' sheets which I cut into 4 even triangles, stack, and glue together using the nasty 3M spray stuff. We got some black fabric which I believe is black flannel and she sewed a "sock" that fits it more or less perfectly.

Dimensions are:

48" tall (as tall as I cared to make them for now, the taller the better) and the other dimensions determined by the size of the rockboard triangles. The front face is 35" wide.

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Don't forget the 1/4 wavelength rule....these kinds of "bass traps" are most effective in the "mid bass" region - which is right where the modal behaviors start to become a problem.

So really, it shouldn't affect much of anything that your subwoofer is cranking out - though it might attenuate some of the harmonic distortions a bit.

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With a 35" face you should have a depth of about 18 inches from the corner to the face- that's a lot of absorbtion! Can Doc calculate the affected frequencies of such a device?

What method did you use to cut the nasty stuff? I remember you muttering about working with the material last winter.

The glue is probably 3M77, I wonder if it was necessary to glue it at all? An alternate method might be to simply 'spear' the triangles together like a giant toothpick going through a tasty sandwich. 2- 3 straight wires run through the stack should effectively keep things from shifting

mmmmm socks mmmmmm

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Cut method: get a carpet knife/safety knife razor thing whatever they are called, extend it all the way out so it's greater than 2" long. Mark the triangles using chalkline and cut down the middle of the chalkline.

Using 1/4 wavelength and assuming I've had enough cofee for math and speed of sound is 1300ft/sec

var lowFreq => (1300 / (feet => (18 *4) /12) )

Around 216hz

The concern with of using too much of the glue is that the glue itself will become reflective if you stick these together with too much glue. I'm not sure if some wooden poles maybe 1/4" in diameter would have the same reflective concern: honestly poles might be much easier than glue. Since you're trying not to use too much glue the damn thing can fall apart while you're carrying it unless you fashion a makeshift "stretcher".

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