# converting closet into bass trap



## Wintermute (Jun 13, 2009)

I have a rectangular room that has (had) a 4ftx2ft closet in one corner. The closet door and door frame have been removed. So I'm left with a 4ftx2ft indentation (ceiling is 8ft high). I was originally going to use the space to hold my HT electronics. But I would have had to run cable under the house to avoid it being tripped over and I just don't want to punch too many holes in the house yet. So now I'm thinking about converting the space into a rectangular bass trap. In my previous home I had built a corner trap out of OC 703 and it worked great. I'm planning on stacking the OC 703 from floor to ceiling with a total of 8" thickness with a 12" air gap to the back wall. I will be sure to seal the edges tight so that air cannot go around the trap. I'll then cover the whole trap with a large piece of speaker cloth stretched over a wood frame to fit the opening. 

My questions are:
(1) is 8" of OC703 overkill? I have 24 2x4x2 sheets of OC703 to work with. Due to fireplaces, patio-doors and windows I don't have a lot of other places to put bass traps.

(2) I'm assuming that my rectangular trap should perform better than a triangular trap, but I don't know the math to back up this assumption (total volume?). 

-Dave


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## fitzwaddle (Aug 25, 2010)

Wintermute said:


> I was originally going to use the space to hold my HT electronics. But I would have had to run cable under the house to avoid it being tripped over and I just don't want to punch too many holes in the house yet.


Did you consider routing wires under crown molding or baseboards?


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## bpape (Sep 14, 2006)

Don't sweat sealing it up. Anything that you'd want to seal it with, bass will go right through like it's not even there. 

8" is not overkill but 8" of gap is likely going to give you the most extra. 12" won't hurt, just won't gain you much, maybe a little.

Bryan


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## Wintermute (Jun 13, 2009)

I've completed the trap over the weekend. The trap has made a significant improvement in the room acoustics. Better than when I had used OC 703 for a four-layer corner trap. Probably due to the larger 8" gap behind the 703. I have enough room for a 12" gap. I think I'll move everything up to see if that helps even more.

Next step is to address the first reflection points in the room. I need more OC 703. My previous source in Northern CA is out of business. Any suggestions?
-Dave


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## bpape (Sep 14, 2006)

Once the gap is equal to the thickness of the absorption, you've reached the point of diminishing returns. Adding the additional gap may extend things slightly but can also introduce a 'hump' in the absorption curve.

Bryan


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## fitzwaddle (Aug 25, 2010)

I got my OC 703 and Roxul AFB from MacArthur Co locally - I'm in So Cal, but I see they have several No Cal locations - http://macarthurco.com/loc.htm . The guy I worked with was very helpful, and the prices and service were good. No idea of course if the same would be true at their other locations, but hopefully so.


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