First Time Trap Building Help

Posted: Wed Feb 06, 2008 11:33 pm

Ok,
Using a guide from YouTube: http://youtube.com/watch?v=iyYUpkpL0gw I'll soon be going about creating my own custom bass traps. Before I get to buyin anything however, I'd like to ask a few questions about the materials.

The tutorial asks for:
4pcs of 1x2x47 inch wood length
4pcs of 1x2x21 inch wood length
2pcs of Good Fabric (60x40) inches each (What do they mean?)
2pcs of Cheap Fabric (26x50) inches each (What do they mean?)
Fastening materials like heavy duty staples, screws, ect.
and
4" of 6pcs Rock Wool or Owens Corning 703 insulation at 38"x24"x4"

So I went to Home Depot and checked out some prices. For the wood, not expensive at all (like $1.00 per plank). The question comes in with the insulation. Now they have Owen Corning but it's noted to be R-13 subnoted as K95 (???). The stats are:
3.5" thick
15" wide
and
32ft long

Now from the looks of it, even though the insulation is not wide enough, I can just put two side by side for the total distance. It's not 4" but close and I don't think 0.5" makes a big difference. Given the length, I'd have the ability to make 4 traps, and the insulation is just $9.96 (graded as wall and acoustic insulation)! I haven't calculated fabric yet but so far, the price looks convincing enough! The question is, will this insulation suffice? Based on what I've read, density of the insulation is almost irrelevant (at least from what I've read about Porous based traps): http://basstraps.net/index.php?topic=29.0

Also, would there be anything else that I could add to increase the quality of the trap? Like I've been over hearing about some sort of membrane thing or what not??? IDK.

Thanks Guys!

Posted: Thu Feb 07, 2008 6:25 am

There's a reason that standard "pink" insulation is not mentioned and Rock Wool/703 is.

That difference is in the density/mass of standard "pink" insulation is far less than that of 703. The density of 703 is on the order of 4 times that of standard home insulation. The density is what offers the resistance to the sound energy.

I suppose you could compress it yourself, but good luck on that... you have to find a way to squeeze 8 layers of R13 down to 4" and I think you would still be too light in density.

Look around the internet for Owens Corning 703 distributors. This is an example of what you are looking for. I haven't priced 703 in quite awhile, so I'm not sure how their pricing is... you should shop around.

Good luck and happy building!

Posted: Thu Feb 07, 2008 7:51 am

Hey,
I applaud DIY mentality - and experimentation

MADMAX said "...That difference is in the density/mass of standard "pink" insulation is far less than that of 703. The density of 703 is on the order of 4 times that of standard home insulation. The density is what offers the resistance to the sound energy."

If you comprese the R13 or r19 stuff to 1/4 of it's thickness it will work - it becomes 4x as dense. It's all about density as MadMax said. Compressing it in flat panels is VERY difficult but I made some cylindrical traps - 1/2 square hardware wire inner core, 8" glass compressed to 2" and another layer of wire outside. Then covered in burlap.

Posted: Thu Feb 07, 2008 11:10 pm

Xtreemmak...you might want to read http://basstraps.net/index.php?topic=29.0 again.

To quote Scott R. Foster "Use a 3 lbs. density in all panels of 4” thickness or greater. In 2” panels we recommend a stiffer fiberglass board such as the 6 lbs. density Owens Cornering 705."

I know things move fast around me too...

Posted: Fri Feb 08, 2008 12:51 pm

Here's hard data comparing 705 and 703 (and 701) below 200 Hz:

www.ethanwiner.com/density.html

--Ethan

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