My GIK Pillar Trap Review

**thewire** · **02-10-09, 05:37 AM**

Placing the 244's over my stage now gives me reults I like. I moved out the subwoofer out from between the stage, placed insulation in there instead, and placed the other couch back in since I had a complaint about that. Checking the ceiling above the back row there is zero abrorption back there. I found some blankets that I stuffed up in the corners.

This is with four 244's across the front stage with some pink behind them in the center, a small amount of pink laying on the back center wall above the sub there, and the seats, and subs moved again. The stage has a 1 3/4" thick peice of plywood added to the top. The roll-off of the subwoofers in the front of the room looks really good. There are a few tiles missing in the back of the room.

Front row with a quick setup. No eq was done, and it doesn't look equalizable.

The back row looks scarry now. I have never seen such a lack of extention back there. This was without the small absorption on the back wall.

**bpape** · **02-10-09, 07:03 AM**

Sorry - been buried. I'll do some checking today.

Bryan

**thewire** · **02-10-09, 07:24 AM**

The highs didn't sound right. The best I could get it to sound was when I placed two 244's at the first reflection points with and additonal one stacked on each pair horizontal, then placed the 2" around my surrounds.

**thewire** · **02-10-09, 07:27 AM**

Quote:

bpape wrote:

Sorry - been buried. I'll do some checking today.

Bryan

That's alright. I appreciate it.

**thewire** · **02-10-09, 03:09 PM**

Here is my 2" on the front wall give or take some adjustments. I had to roll the High Power Screen against the wall while feeding the foam into it and then placing it back into my original box with a foam tube I wrapped in paper towls. The screws holding the frame in place are stripped and my drill will not open to put in a new bit. I have a second frame which was originally designed for it becuase this was a replacement screen from when I had help painting the room and they had painted the previous one on accident.

**thewire** · **02-10-09, 06:46 PM**

Did you check on mineral wool today? I tried calling IIG but the message said they were not in the office.

**bpape** · **02-10-09, 08:41 PM**

Actually, I went to call and realized I don't have the contact info in my new phone. Going back through my files from last year to get the info.

Bryan

**thewire** · **02-11-09, 12:41 PM**

I burned some custom ticks and beats to CD and I notice that placing absorption at the side walls in the middle corrects some coloration in the 80Hz area where it instead of sounding localizable from the front to the back of the room it sounds like it is more in phase. I notice that the 250Hz seems to reflect of my ceiling and bounce to the floors corners with some build up there. There is some higher pitched reverberation that seems to dominate on the right side of the room in the front, and the left side of the room in the back. This seems related to the second reflection points. If I were to address these problems, I wonder if adding standard R19 insulation in the back of the room would sound alright and less punchy.

**thewire** · **02-11-09, 02:15 PM**

Very interesting. I checked the reference material for which I had the problem with and placing some the 244's at the side walls midpoints the bass sound very even thoughout the room now but there is some deep sounding bass? from the left or right channels. It does not feel distracting that way. That has to be something with the 244's on the front wall. I think I just need some more 244's and I have listened to alot of material with them at each location, so I will go ahead and order a couple more pair of those for now unless anyone would suggest otherwise.

**hjones4841** · **02-11-09, 05:37 PM**

I don't have any experience with the 244s, so I cannot offer suggestions. As posted elsewhere, all of mine are Monsters. It seems that we both have done our share recently to keep GIK in business

I notice that your avatar lists media reviewer. Is that your profession? Is your room used in your business? I am an electrical engineer in nuclear power generating plant design. I always envisioned a career in electronics, but when I graduated from college in 1971, the space program was almost over and few electronics firms in the Southeast were hiring. So, power engineering pays the bills for the electronics addiction

**thewire** · **02-11-09, 06:02 PM**

Quote:

hjones4841 wrote:

I don't have any experience with the 244s, so I cannot offer suggestions. As posted elsewhere, all of mine are Monsters. It seems that we both have done our share recently to keep GIK in business

I notice that your avatar lists media reviewer. Is that your profession? Is your room used in your business? I am an electrical engineer in nuclear power generating plant design. I always envisioned a career in electronics, but when I graduated from college in 1971, the space program was almost over and few electronics firms in the Southeast were hiring. So, power engineering pays the bills for the electronics addiction

Yes I review movies here over in the Media Review forum. If not I would be unemployed like the other 85% in my area during the winter months. Hopefully it will be a better season here at the lake than last summer when it had seemed to rain or storm just about every day. My grandfather always tinkered with electronics and gadgets and my great great grandfather had contributed to MGM for them to get started so it has always been a hobby of mine. It makes my other family members are very jealous when they come over.

I recently took a trip up midwest and got THX certified. A couple summers ago I had inventation from the academy awards to review movies which I would have taken but my family wanted me to have a "normal" job. I might have to write them back to see if they are still interested or not some time.

**thewire** · **02-11-09, 06:50 PM**

I Ordered two Monster traps, but I will get some more 244's later this week. I could probobly get the insulation free.

**hjones4841** · **02-11-09, 07:17 PM**

I think you will be pleased with the performance. At least on paper, they are quite a bit more effective in the lower octaves than the 244s. Bryan indicated that stuffing some pink insulation behind them may improve absorption performance in the lowest bass. I haven't tried that yet.

There is about an inch or so gap at the back of the trap between the back of the material and the back edge of the frame. I suppose the intent is to provide that as an air space even if the trap is pushed against the wall. That may even be there on the 244s.

Something to remember is that GIK will make a custom size of any of their traps for a very nominal fee (I suppose as long as it is within the 24x48 standard). And if you buy more than one, the surcharge for the other custom ones of the same size is even less.

**thewire** · **02-11-09, 07:48 PM**

Quote:

hjones4841 wrote:

I think you will be pleased with the performance. At least on paper, they are quite a bit more effective in the lower octaves than the 244s. Bryan indicated that stuffing some pink insulation behind them may improve absorption performance in the lowest bass. I haven't tried that yet.

There is about an inch or so gap at the back of the trap between the back of the material and the back edge of the frame. I suppose the intent is to provide that as an air space even if the trap is pushed against the wall. That may even be there on the 244s.

Something to remember is that GIK will make a custom size of any of their traps for a very nominal fee (I suppose as long as it is within the 24x48 standard). And if you buy more than one, the surcharge for the other custom ones of the same size is even less.

I thought about trying some insulation behind the 244's. It is also 1", 1" 1/4" I think actually. I could fit some pink behind it but I don't have much to spare at the moment. I was looking at the absorption coefficients yesterday of the 244 again and I saw the Monster and looking at them they seem to center right around the problem target frequency in my room. I kept putting them in the checkout, leaving awhile comming back, putting them back in. I'm glad those are ordered finally. I talked to Bryan before about custom sized traps for the small area on my stage, but the cost was out of my price range at the time. Those are still on file should I decide to do that, but with the new Pillar traps there they would be slightly smaller. I'm pretty sure the insulation on there does at least at decent enough amount of absorption.

I could see the Monsters helping above the 244's at the first reflection points or on the front wall. Since I can freely move the speakers I'm not sure I would benifit having them at the first reflection points. My speakers mostly are performers in the mid-bass area although they do go down to 28Hz. It's all these subwoofers in a concrete room that are so difficult. Having the subs at each walls midpoint is suppossed to loose around 12dB - 18dB that way, but I think that I did not loose near that much.

**thewire** · **02-12-09, 12:24 AM**

Replaced a tile on my ceiling with a panel, moved insulation from the front stage (except corners) to the rear of the room, placed left reflection point panels on the stage with the other 244's and took the other 2" panel at the top of the screen wall into the other room to at least maintain symmetry on the front wall. I lost a couple decibals of SPL and equalized to a lower target loosing some headroom but I'm not sure how much. I turned my subwoofer level up so that is nearly +4 higher than the mains. I probobly should just eq to 25Hz which I may do next time but I thought it might be interesting to equalize some around the first room mode. This one is +-9dB. What is more important is what this sounds like.

**hjones4841** · **02-12-09, 05:34 AM**

I had thought about putting a couple of Pillar or Table Top traps in the room to replace two tables that I removed. I would be interested in your take on the peformance of the Monster vs. the Pillar. From the website, it seems they are similar since there is absorption from all sides on the Pillar.

I am still simply amazed at the difference traps made in my room. Wife and I watched AI last night and I kept having to turn the sub down (and the volume down on some singers

). The bass is so much more omnidirectional now, probably due to taming peaks in the mid bass more than anything else.

**thewire** · **02-12-09, 01:53 PM**

Quote:

hjones4841 wrote:

I had thought about putting a couple of Pillar or Table Top traps in the room to replace two tables that I removed. I would be interested in your take on the peformance of the Monster vs. the Pillar. From the website, it seems they are similar since there is absorption from all sides on the Pillar.

I am still simply amazed at the difference traps made in my room. Wife and I watched AI last night and I kept having to turn the sub down (and the volume down on some singers

). The bass is so much more omnidirectional now, probably due to taming peaks in the mid bass more than anything else.

I will do a comparrison when they arrive.

I think that I will have to measure/listen to the performance of each in a different room to base my opinion on the two, but I'm not entirely sure. With the Pillar Traps I just move them around the room and listen to the improvements, then measure. It was much easier than to measure, place them, then have to move them again to improve the results. It's not as quick a proccess to do that with the 244's, but if the Monsters are close to being like the Pillars, setup should be simple.

**thewire** · **02-16-09, 05:32 PM**

This is with 3 GIK 244's hung vertical at the first reflection points on each left or right wall, the 2" panels along the stage, Pillar Traps in the front corners with the insulation under them, added insulation inside the right ceilings corner, and insulation in the corners inside the Helmholtz Resonators in the back. I removed the reflective board in the ceiling above the left center and right speakers as well.

This gave me a large dip from the ports at the bottom of the speakers again.

I measured at 12" for the left speaker, then again at the floor.

I borrowed a 244 from the furthest first reflection point on the right wall and placed it on the floor horizontal next to the speaker, then remeasured. I then measured from the seat again. I looked at the the back row and the front row again. The Monster traps should be here tommorow. I still think I need another pair of 244's after seeing this problem come up again, and treating the back wall and front wall could wait. Suggestions are welcome, and I am undecided after several days of thinking about this which is more important. I tried with the insulation behind a couple of the 244's.

**hjones4841** · **02-16-09, 07:38 PM**

I am sure you thought of this already, but take some measurements of the 244 vs. Monster in the same location. It would be interesting to see how well the performance difference in your room correlates to the test reports. The test reports are what convinced me to go all Monster, since I was starting from scratch with traps and needed to maximize absorption per unit size. I suppose there is a tradeoff, tho. Absorption distributed thruout the room vs. more concentrated absorption at fewer places.

**thewire** · **02-17-09, 07:59 AM**

Quote:

hjones4841 wrote:

I am sure you thought of this already, but take some measurements of the 244 vs. Monster in the same location. It would be interesting to see how well the performance difference in your room correlates to the test reports. The test reports are what convinced me to go all Monster, since I was starting from scratch with traps and needed to maximize absorption per unit size. I suppose there is a tradeoff, tho. Absorption distributed thruout the room vs. more concentrated absorption at fewer places.

7" is as thick it goes for first reflection points I think. The Monsters control a more broad-range of frequencies, and are highly effective in those where music is critical. Right around the left and right speakers from where those sounds are coming from where I have boundary interferance could very well be a good place for them, and it could avoid exciting some slightly my room modes that are critical to left and right stereo imaging. As the pressure changes in the corners the percieved tonal balance from them changes, and this effects the important acoustic foci. I will give them a try there.

The back of my rooms corners effect the same frequencies, which is why I placed some insulation there.

**thewire** · **02-17-09, 12:57 PM**

This morning I have done my best to decouple the subwoofers from the side walls. The side walls are not attached to the ceiling except in small areas with caulk to prevent rattles, that are partially sealed off using fabric. The left wall is staggered, and the right, front, back walls are semi staggered with the framing attached to the concrete using liquid nails. Each board inside the HT is caulked or glued then nailed into place.

The subwoofer in the back I removed the stage, then sat the subwoofer on half dozen or so concrete tiles that I surrounded with insulation. The side ones I cut a hole under the Subdudes, added more insulation, then screwed them into the platforms using many nails so that I could space them from the wall, allowing the ports to breath. There is some area to absorb some energy from the ports on the side walls as well. The insulation will later be covered in fabric and I will refinish the subwoofers eventually with paint instead of the layer on them.

This should help for the testing purposes, and I might gain back some acoustic energy from the subwoofers.

**thewire** · **02-17-09, 05:52 PM**

Here are the test results with the traps next to my main speakers ports at the floor on concrete. I placed a 244 or Monster in each corner in front of the corner trapping laying horizontal on the floor. They were beside the bottom of the 244's and spaced from the wall the distance of the 244's but the 244's are not perfectly flat against the wall. I measured each speaker with and without the subwoofers on, the subwoofers by themselves, and then repeated the test for each different trap. When a different trap was tested, it was removed from the area and brought into the house, not into the lobby next to the theater. The mic was not moved, and levels were not adjusted. You can click the thumbnails to see the larger images.

244 Traps

right no subs 244 1 sweep at 256K 1/24 smoothing

right xo 244 1 sweep at 256K 1/24 smoothing

left no subs 244 1 sweep at 256K 1/24 smoothing

left xo 244 1 sweep at 256K 1/24 smoothing

before equalization subwoofers with 244 traps5 sweeps at 256K

Monster Traps

right monster no subs 1 sweep at 256K 1/24 smoothing

right monster xo 1 sweep at 256K 1/24 smoothing

left no subs monster 1 sweep at 256K 1/24 smoothing

left xo monster 1 sweep at 256K 1/24 smoothing

before equalization subwoofers with monster traps 5 sweeps at 256K

example subwoofer equalization with monster traps 1 sweep at 256K

example after subwoofer equalization with one main 1 sweep at 256K

**hjones4841** · **02-17-09, 07:15 PM**

Interesting. Looks like narrower ringing frequency distribution in the 23-24 Hz range with the Monsters but with a higher amplitude. I think that happened in my room for the mods done last weekend. However, on mine the whole amplitude from 20-40 or so went up on the FR response plot. I am not seeing that on yours, unless you normalized the volume.

How many filters did it take to flatten the FR? Looks good.

**thewire** · **02-17-09, 08:05 PM**

Quote:

hjones4841 wrote:

Interesting. Looks like narrower ringing frequency distribution in the 23-24 Hz range with the Monsters but with a higher amplitude. I think that happened in my room for the mods done last weekend. However, on mine the whole amplitude from 20-40 or so went up on the FR response plot. I am not seeing that on yours, unless you normalized the volume.

How many filters did it take to flatten the FR? Looks good.

I'm not sure how accurate that is under 35Hz - 40Hz. Each time I measure the ringing changes from around at least 3 and up to 5 or 6 of the slices in the waterfalls. I did notice the response changing when I went from the 244's to the monsters quite easily, espicially in the room modes I was targeting for the test. I used 6 filters for my subwoofer. The target is a 120Hz crossover slope for LFE so I need to add some more filters than if I were to use a crossover from something such as a CD input. The desription of the optional settings on my Outlaw 950 are:

Quote:

6-channel analog input
bass management off: full-range speakers receive full-range signal, subwoofer receives LFE signal plus information below 80Hz from the other five full-range speakers ("double bass" condition); subwoofer also has a filter that discards material above 120Hz on the LFE input signal (material that subs typically can't reproduce well)
bass management on: full-range speakers receive all information above 80Hz, subwoofer receives LFE signal plus information below 80Hz from other five full-range speakers; subwoofer also has a filter that discards material above 120Hz on the LFE input signal (material that subs typically can't reproduce well)

I have it set to the on position. The subwoofers themselves have no crossover, and are only powered by mono amps.

More on that here. To measure a more accurate reading I use a CD that I burned with REW of Pink PN in my CD player to check things when I am happy with results I get in the sweeps.

I didn't touch any volume except that I calibrated levels of the mains to the target before I began measuring while I had the 244's in place. The settings were pre/pro master gain -10, subwoofer 0, mains +3 or +2. I have the gain turned up in REW so that it is a 75dB target instead of raising the gain on my pre/pro and lowering the volume in REW for the 85dB target.

**thewire** · **02-17-09, 09:57 PM**

I think that I see what you are saying about being effective down at 40Hz. In my measurements if I zoom in to 40Hz - 200Hz, and then lower the graph down I can see that there is a pretty effective amount of absorption around that range in the waterfall graphs.

yellow = Monster Traps
blue = 244 Traps

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