# Bass trap density



## kadijk (Jan 23, 2011)

Based on what I've read so far, corner bass traps are best made of loose type batt insulation. Provided I have around at least 24" of surface area facing the room. Pounds/cu ft of normal r20 batts is? 1/2 pound or so? I have access to spray foam for house insulation that is also 1/2 pound density. It's called icynene.(currently contracting a house for a client that's being completely foam insulated). My thought is this foam, encased in a 2x2 frame, covered in cloth, would make a slick corner pillar bass trap. Any thoughts?


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## bpape (Sep 14, 2006)

For the density, it really depends on thickness. For a typical 17x17x24" triangle, something like OC703 or equivalent will work best. For thicker, you can use the lighter material.

In any case, the Icene is not acceptable. It forms a closed cell structure that has little to no acoustic value.

Bryan


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## kadijk (Jan 23, 2011)

Thanks Bryan. The icynene installer/owner praises its sound and acoustic properties. I didn't have the heart to disagree before I asked the density, which I thought at 1/2 pound would be appropriate. I guess he'll continue in ignorance. And I won't use it.


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## SAC (Dec 3, 2009)

Icynene's acoustic properties are substantial, but not in the way you might think.

The advantage that it offers is that it expands and fills voids and seals all cracks, rendering the boundary airtight - thus defeating many flanking vectors that defeat traditional absorbent material treatments. 

But as Brian has aptly observed, the closed cell material itself offers little if any absorbent advantages. In fact, in itself it will tend to be a more reflective then absorbent surface.

So their claims are justified, but one must define the factors about which one is focused in order to determine if said benefits are advantageous in a particular application.


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## bpape (Sep 14, 2006)

Agreed. From an ISOLATION standpoint, it can be very useful.

Bryan


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## kadijk (Jan 23, 2011)

Learning,learning,learning. Thanks guys. I'm going to try getting a hold of a book referenced in another thread regarding absorption, diffusion and acoustic treatment principles. It's always a good day when one can learn something.


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