Discuss Corner trap depth vs efficiency in the Home Theater Installation | Systems forum.
I don't think this is really threadjacking, but a related question. First of all, I was somewhat confused about which ...

**drrick** · **06-23-09, 11:50 AM**

I don't think this is really threadjacking, but a related question. First of all, I was somewhat confused about which is more effective, 12x12 squares or 17x17 triangles? I guess the 17x17 seems intuitively to me like it would be better, but I'm learning that I shouldn't just trust my instincts with acoustics

The second question I have is related to my own setup. I currently have a 4 inch thick 2'x4' panel straddling the corner. Would it be better to make this into a chunk absorber or not? Obviously with a chunk absorber (using the same material) I'm only going to be going up the wall 32" as opposed to the 48" I'm currently covering. What's the tradeoff, and is one preferable in different situations? I'm just trying to figure out the most effective approach. Thanks!

**bpape** · **06-23-09, 12:11 PM**

Actually, a 12" square will work a little better. The 17x17x24" has 17" only at the wall surface and at 45 degrees is 12" thick. The 12x12" is 12" thick both ways full surface and is 17" thick at diagonal. The issue with that is that it takes up more space in many situations.

If you change the 4" thick to chunks, you'll get deeper extension, but at the cost of 33% of your surface area. The other option is to compromise and do 8"x8" chunks which will give you actually a little more height and similar extension to what you have now.

Bryan

**drrick** · **06-23-09, 12:34 PM**

One further question just to clarify my understanding. I know the general rule is that more surface area is always better. Is there ever a time where what I described might be beneficial (e.g. is it possible that you might see enough gains down low with the chunk that isn't as tall that it would be worth sacrificing the surface area)? If you cut down the surface area, basically you're losing overall effectiveness right? You'd basically be trading increased absorption down low for an overall reduction in absorption everywhere else. Am I understanding things correctly? If so, it seems like the best option is to either stick with a similar surface area or get more material! (with the latter obviously being most preferable)

**bpape** · **06-23-09, 12:41 PM**

Is there EVER a time? Probably - but not usually. If all of your issues are still able to be resolved with less surface, then it might work.

What you're trading is potentially dealing with lower frequencies vs. more control of decay times.

Bryan

**drrick** · **06-23-09, 05:46 PM**

Thanks! That clears it up for me. I appreciate you taking the time to help me understand some of these acoustic principles.

**bpape** · **06-23-09, 06:40 PM**

No problem at all. It's not a simple thing. There are a TON of variables involved. If you'd like to give a little more info:

- room dims
- what it's used for
- how many people
- how many and what kind of seats
- how the room is built

I can take a WAG at it. A sketch would be a ton of help too.

Bryan