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

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Discussion Starter #42
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:bigsmile:). 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. :T 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.
 

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Discussion Starter #43
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.







 

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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.
 

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Discussion Starter #45
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. :yes:

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

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Discussion Starter #46
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.
 

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Discussion Starter #47
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

 

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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.
 

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Discussion Starter #49 (Edited)
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:

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.
 

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Discussion Starter #50
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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Discussion Starter #52
Yes they help quite alot. I was very impressed with listening to the entire Transformers movie while watching speakers move. :coocoo: I ordered a case of 6 2" OC 705 and am buying a Rane SSE-35 Home Theater Equalizer. I was not pleased with sound from the front wall with my compressed insulation, and the back of the rooms upper corners sounded like the bass was lacking somewhat, so I want to put the rest of my insulation back there again. I hope that my screen will act similar to having a layer of FSK. I may end up leaving the back of my room without absorption and get some dipole surrounds. The back row is not real concerned about having more treatments, and they are already happy with the improvements thus far and think it is fine how it is. I will listen carefully for slap echos off the back wall again, but I didn't hear it last I checked, and it may have had something to do with how I have changed the riser more recently.
 

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My other two Monsters shipped today, so I should have them tomorrow afternoon (just one night to here from Atlanta). I will make a few measurements this weekend and post them. As stated earlier, I am limited as to where they will fit. Try putting a R30 batt behind the Monsters - Bryan said that might help in the lower freqs.

Not sure what you mean about the screen acting as FSK. Is it vinyl on a frame? If so, it should be reflective to mids/highs and not do much below that.
 

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Discussion Starter #54
My other two Monsters shipped today, so I should have them tomorrow afternoon (just one night to here from Atlanta). I will make a few measurements this weekend and post them. As stated earlier, I am limited as to where they will fit. Try putting a R30 batt behind the Monsters - Bryan said that might help in the lower freqs.

Not sure what you mean about the screen acting as FSK. Is it vinyl on a frame? If so, it should be reflective to mids/highs and not do much below that.
Good idea. I have more than enough for that area on my stage, and I don't like it compressed, so I will put that behind the Monsters. I actually forgot to try that I was so busy.

The screen is a High Power Da-Lite screen that has a vinyl back on it. I think that I remember reading that FSK was not needed with a screen in front of it, but I don't recall the difference between a vinyl screen and FSK. I'm just hoping it reflects enough back above ear level.

I have been busy today trying to get things setup. It seems easier to hear higher q resonances after adding the Monsters. I'm trying a couple layers of wood (over 3") added to the face of my Helmholtz Resonators and stacking the concrete tiles on the top of it. It sounds like it is helping in the back of the room at least. I'm also going to try various things above the first reflection points to see if I can improve anything with that, and make them more decorative. That's something I have not tried yet so I will give it a try. I hope to have things setup with what I have by the end of the night.

Do you have planned where you are putting the next Monster traps when those arrive?
 

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I will probably start with them in the center rear wall, in front of a brick fireplace on the GIK stands. That is where Bryan initially recommended them for absorption from that wall to the center recliner. They worked well there, but are the ones I mounted horizontally in the rear corners. I can slide them around easily to find the 1/8th wavelength for the 27Hz peak that I have. Don't know what the point of diminishing returns is for my room; I will have 5 Monsters along that 12.5ft wall, counting the ceiling corners and the ceiling center, plus the two up front in the corners.

(Hey, GIK, how's about a quantity discount for thewire and me:yes:)

I sent Glenn an e-mail about a simple mod to the GIK stands. Due to moving the first traps around, the wood blocks that fasten the stands to the traps were coming loose. They are held in place with two short nails. I drilled a small pilot hole between the brads and put in a 1" drywall screw. Sure tightened them up. I had thought about using wood glue, but was out of it. Glenn replied that they will look at using that mod.
 

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thewire: I meant to ask you what brand/color of black paint worked best for you? Folks at AVSforums like Behr Mouse Ears, but say that it badly shows marks. I used a Glidden flat with a Behr color that Home Depot mixed for me. Color is fine, but has a slight sheen where light from the screen hits it.

Before I blacked out the whole ceiling, I covered two rows of tiles closest to the screen with Parts Express black grill cloth - looked great with no reflection or sheen, but too expensive to do the whole room.
 

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Discussion Starter #57
I will probably start with them in the center rear wall, in front of a brick fireplace on the GIK stands. That is where Bryan initially recommended them for absorption from that wall to the center recliner. They worked well there, but are the ones I mounted horizontally in the rear corners. I can slide them around easily to find the 1/8th wavelength for the 27Hz peak that I have. Don't know what the point of diminishing returns is for my room; I will have 5 Monsters along that 12.5ft wall, counting the ceiling corners and the ceiling center, plus the two up front in the corners.

(Hey, GIK, how's about a quantity discount for thewire and me:yes:)

I sent Glenn an e-mail about a simple mod to the GIK stands. Due to moving the first traps around, the wood blocks that fasten the stands to the traps were coming loose. They are held in place with two short nails. I drilled a small pilot hole between the brads and put in a 1" drywall screw. Sure tightened them up. I had thought about using wood glue, but was out of it. Glenn replied that they will look at using that mod.
There is such thing as to much and there is also to little. The tonal balance and decay is important but there is a an amount that you will have to decide what sounds right. There are recommendations for how many sabins to absorb and also how it placed in the room. Many acousticians have a set of guidelines for how much to use and in what ways. You will want to find what works. It really takes more than one person to complete a room. It is a collabrative effort and I think that Bryan or others will tell you if you have overdone something and I read him telling someone when something is too much.

Some goals of home theater are:

  • Clear dialog
  • Precise sound localization
  • Spacious surround
  • Smooth sound movement
  • Even tonal balance
  • Full dynamics
  • Transparency
  • Every seat a good seat
 

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Interesting point that you made about dialog. I would have never believed that bass traps could increase clarity in the center channel, but that is what happened. I originally thought that I had overdone it in mid/high absorption but after listening for a while I think it is just fine.

Dynamics in my system have never been a problem. The speakers are extremely efficient (104db/1watt/1meter) so getting very loud is easy, although at times I wish I had a second sub. I played an old CD of organ music Sunday at high volume and could tell the Velodyne was limiting itself. 99% of the other times it is enough, tho.

The Monsters may have been delayed by Fedex - multiple severe weather events last night between here and Atlanta, including tornadoes. News said that I-20 was shut down both directions about 60 miles east of here; never heard why.
 

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Discussion Starter #59
thewire: I meant to ask you what brand/color of black paint worked best for you? Folks at AVSforums like Behr Mouse Ears, but say that it badly shows marks. I used a Glidden flat with a Behr color that Home Depot mixed for me. Color is fine, but has a slight sheen where light from the screen hits it.

Before I blacked out the whole ceiling, I covered two rows of tiles closest to the screen with Parts Express black grill cloth - looked great with no reflection or sheen, but too expensive to do the whole room.
I switched to Disney "Lamp Black" because the Home Depot in our area said they did not carry it anymore. I had my previous can for them to match which had been the Behr Mouse Ears. I have to keep the paint on hand to touch up the walls if they get dirty or scratched. I went to a paint store and they said they didn't carry black so I looked at Wal-Mart and Lowes, then Home Depot where I found the Disney Mouse ears. I thought it was best so I went with that. I was not bias because I had not researched it. I figured nobody used black but I had forgotten about ceilings and screen walls then. I had not visited the forums for a few years when we had the HT first built. I had a few weeks to get it done with the framing, electrical, walls, HVAC, and so on with help from the construction crew.

I used a grey primer because the walls sucked up the black very quickly and because they were textured it made it more difficult. I used a black light to find places that I missed. I had to apply three coats of the Mouse Ears after the primer. The extra coat was after someone decided to sweep the room.

It's not reflective much, and not enough to cause a distraction in my room. It sucks up alot of light so I had to get some track lighting in the back of the room. That worked out really well because I can aim it down and watch a movie without the room getting fully lit up, ruining the image, or having to bring a lamp into the room to take photos. The photos really make the room 10X more a mess than it is. I seldom take as much time to clean between projects as I used to.


I removed the face of my Helmholtz Resonators for which I will cover in a fabric frame. I reinforced the left and right walls with very heavy wood on the left wall and some 1 3/4" plywood on the right wall behind the panels. I moved the insulation off my stage to the rear corners inside the now...traps. They are about 1/4 full of insulation each. The insulation behind the Monster Traps helps also for the very low ringing, but the mains response is now very sensitive to the back of the room after reinforcing the walls behind the panels and there isn't enough insulation to fix the dip at around 168 Hz. It's not as bad as it was to start with. The response went up 5dB. I added 3 or filters but I forget. I will get back to that later, but the 40Hz dip is better which I am proud to have accomplished today. This is the one that REW recommended.





I could not buy the Rane eq. During the last 3 hours people started bidding and the price doubled so I woln't be getting that soon. The person selling has been selling many of them lately so I will keep an eye open. I will probobly get something else besides an eq. It would be nice to eq the center channel.
 

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A comment on the dialog...

That actually is one of the most commone 'symptoms' of a room that has too little bottom end control. It's a lack of clarity in the center. It's also that 'can't hear the dialog so we turn it up - but then the effects are too loud so we turn it down' syndrome.

What's happening is that the bass decay time is out of control and the ringing is masking the dialog. People don't realize that male voice can easily go below 200Hz.

Bryan
 
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