# Table treatments?



## gtpsuper24 (Jun 24, 2009)

Ok have been looking at those GIK table/ Pillar traps and thought about making my own. Planning on using ats acoustic board 2" and use 2'x2' squares and stack them 18" high, make a frame and put a top on it. Is this good or bad idea. Got my superchunks in the front 2 corners, I finally go rew working so now i'm trying to figure out any thing else to do. Thanks


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## bpape (Sep 14, 2006)

That will work - though they're bigger than the Pillars. Also, if you want better performance, you'll want them taller than 18"

Bryan


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## gtpsuper24 (Jun 24, 2009)

Well for the tables I could go with a 24" cube. The pillars i'm not sure yet what dimesions i'm going to do. After I run REW is there a way to test to find out were the best place to put treatments? I figured I could do the 24" cube tables and if I didn't get any decent results, I could cut them in half and do superchunks in the wall ceiling corners.


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## bpape (Sep 14, 2006)

I guess the point is that you'll want more than just the lower or upper corners depending on what else is in there besides the existing chunks.

After REW, you can look at where the peaks and nulls are and start looking at overlaps to dimensions of the room, dimensions from speaker to wall, seating to wall, etc.

You can also do a walkaround and listen for places where the bass seems overdone while playing the frequency where the peaks exist.

Bryan


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## gtpsuper24 (Jun 24, 2009)

I got some results running rew, I moved the sub to two different places. Limited on were I can go with it right now. Yellow is the right side and blue is the left side. Any ideas on anything that can be improved.


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## gtpsuper24 (Jun 24, 2009)

I'm new to REW but the yellow looks like its much better


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## gtpsuper24 (Jun 24, 2009)

Ok I did a reading at the location I would like to put the table trap. Tell if I did this wrong, but I stack a few dvd case up to about 8inchs off the floor and laid the spl meter on it, at the listen postion there is a 58-60hrz null, that my main focus right now, so hopefully by fixing it even just alittle nothing else peaks or null somewhere else. Red waterfall is future table location maybe. I noticed a peak at/around 60hrz


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## bpape (Sep 14, 2006)

You need to measure where you sit. 

The first 2 measurements have the aberrations in basically the same place. If the sub was sitting in the same place front to back - just different left to right, then it could still be positional with the sub. Try the sub on either side but forward or back say a foot.

If no changes, then it's likely positional to your seating. Try with the mic a foot closer to the speakers.

Bryan


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## gtpsuper24 (Jun 24, 2009)

So if I want to keep it on say the right side, yellow, I should take readings by moving the sub closer and further from the wall? Looking for the best reading? When I took the blue measurement and the yellow, I held the spl at ear height, with the spl mic pointed up. So from what I can tell the yellow waterfall has a null at 60hrz, and I should run a continious 60hrz tone? Similar to the subwoofer crawl, but I'm listening for a location where the tone is the loudest and that should be a good place for a table trap or something correct? I have acoustic fiber board so by making a table trap for example isn't really going to cost me anything, and I decided to go 24"x24" just cutting the boards in half, so if it doesn't work I can use them for something else without needing to throw them away. Should I use sine wav in the rew generator or is there something better?


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## bpape (Sep 14, 2006)

You can try the crawl. It may or may not help with a null. It's more for finding peaks like the one you have at approx 45hz.

As I said, try just taking measurements with the sub moved and/or the mic (seating) moved to prove what it's related to. Just remember to do only one at a time so you only have one variable.

Bryan


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## gtpsuper24 (Jun 24, 2009)

If i'm trying to tame the 45hrz, wouldn't that need quite alot of depth and sizeable treatments? My superchunks in the corners are 17"x17"x24"x8' I was thinking about getting 4in thick 703 panels and putting them on the front of the superchucks to add some more depth to it. I guess my thinking was if I found a 60hrz peak somewhere in the room, I would put treatments there and that would help possibly raise the null? Would the room benefit from a BFD to help tame the peaks? I thought treatments were more for nulls and peaks needed EQed.


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## gtpsuper24 (Jun 24, 2009)

According to brucek my reading were off on the freq axis so they're fixed now.


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## bpape (Sep 14, 2006)

If you spend the time with placement, you can drastically reduce both peaks and nulls. In the 40's is tough and is generally best addressed via placement prior to treatment. To get into the 40's, you'll need 6" minimum.

Also, you can treat the corners all you want but if it's a modal issue based on width or length, the corners won't address it. It's likely the rear wall and that's what would need to be addressed.

If you can get to a point where you can cut the null in half or move it higher in frequency based on distance, you'll have an easier time.

Bryan


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## gtpsuper24 (Jun 24, 2009)

Well I ran a sine wave at 59.5hrz and 60hrz and walked around the room to see where it was the loudest and the front left corner is were it is very loud, boomy, everywhere else it can not be heard. I tryed moving the sub out from the front wall closer to the center of the room and then closer to the wall and it didnt make much of a difference. So putting some type of treatment in the front left corner, that would help with decay time and help raise the null some correct?


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## bpape (Sep 14, 2006)

Potentially, yes. That's usually more of a plan to identify peaks. Remember that 2 'not too loud' waves coming off opposite surfaces can meet and cancel (nulls). 

Again, have you tried moving the mic to see if it's positional to the seat?

Bryan


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## gtpsuper24 (Jun 24, 2009)

Well I many measurements and I did the "crawl" to find the peak at 44-45hrz and found that its in the right rear corner. I had just a few panels, just enought to do about 32inchs. So I put them about halfway in the corner, centered. I know its not enought, but just to test it out and the peak dropped just slightly and the null raised just slightly, so I will be filling that corner in with larger bass chunks. The left rear corner isn't really possible to treat only the top 30inchs, no other way around that. I did a couple of measurements around the seating area foot to the left and right and forward and neither made any difference in the peak or null, but a foot or so forward was smoother response in the 70-90hrz range almost completely flat.


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## bpape (Sep 14, 2006)

OK. If you can fix one problem with placement without hurting anything else, that's a good start.

Bryan


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