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Discussion Starter #61
Good analysis. I have tried a matching center channel and I had similar results. I hope treating the front wall helps.

I just noticed that my speaker ports on the bottom were both plugged with foam. That should raise the bottom frequencies some. For some reason my surrounds drivers and mains drivers do not look alike. In bringing the speakers into the room my mains did not match, and I had brought the surround up front thinking by other speaker was a main. I had checked the ports, but I did not check close enough obviously. That could explain the 250Hz ringing in the graphs. With DVE at high levels my speakers did not pass the buzz test at 250Hz. My previous review of the GIK traps still stands as I had that problem prior to plugging the ports, but I will give my impressions of with and without them again.
 

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Fedex delivered the other two Monsters at 9 this morning - not bad since they only left Atlanta around 3 this morning. I will at least put them in the room tonight. Kinda limited on "play" time after work. Wife expects the system to be ready for the evening TV viewing by 7 p.m.
 

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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
This may explain something that happened 10 years ago. I had a Klipsch Academy for center channel that I sold (sure wish I had kept it!) and replaced it with a Belle Klipsch (gussied up La Scala). I expected greater dialog clarity with the Belle but actually the Academy was better. The Academy had been on a stand about 18" or so off the floor.

The Belle is floor standing, putting the bass horn very near the floor. I bet that excites more room modes than the Academy did and could be the reason I am getting better dialog clarity now that I have traps in the room. Interesting.
 

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Discussion Starter #64
I took some new measurements this morning after after taking the foam out of the left and right speakers. I found some in the back left surround also. That fixed the dip around 168Hz for the left and right speakers. :jump: Here is a decay of every channel. :ponder: I used a 80dB target by turning down the level in the pre/pro after I calibrated levels with my THX optimizer. The level of the pre/pro after that was -3 for the subs and -3 to -2 for the other channels.

Left channel


Right Channel


Center channel


Right surround


Left surround
 

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Discussion Starter #67 (Edited)
Here are photos of the new bass traps in the back of the room. I want to add some cherry stained trim. I finished the fabric already but I need to trim off some of the extra.
The holes behind the couches (there are a total of 4 on each) near the subwoofer raised the 40Hz dip and adding insulation to the corners improved the ringing.





Here is how the traps look right now in the front of the room. I need to put some of my leftover carpet, fabric, reflective material, larger carpet and recarpet the whole areas, or something to hide the holes where my other 2" panels were hung. There is some insulation or something on the wall near one of the holes that have a couple of the screw anchors you can see above the traps.

 

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thewire: Please help me understand how to interpret the spectral decay plots. Here is mine with center & sub driven. What am I looking at/looking for? Thanks.
 

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Discussion Starter #70
My jaw drops.

Nice work. Thanks for sharing
Thanks. Action scenes in the HT are starting to be pretty realistic.

thewire: Please help me understand how to interpret the spectral decay plots. Here is mine with center & sub driven. What am I looking at/looking for? Thanks.
I use spectral decay to look for an even amount of absorption and to compare that with reflections trying to balance the tone. The blue ones at the bottom go up when I treat I null, and they also go can go down when I treat a peak. I study the spectral decay and look for modes nearby when I am treating a null or peak to see how the effectiveness directly related to the nearby modes. When they seperate and the different colors are spaced futher apart then there is less coloration to the sound and it sounds smoother. If there are valleys or peaks that are not falling directly bellow previous ones above that the bass does not feel right as it decays away.
 

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Discussion Starter #72
I picked up four things of R30 unfaced, paneling nails, and trim for the rear traps from Lowes. The trim has a smooth curve to it. The insulation should allow me to get the concrete off the rear traps, and remove the plywood in the ceiling in the back of the room above the center/rear wall, then fill the corner there. I need some around the tri-corners in the back of the room also. I hope that this will improve the surrounds some. If the rear corners are anything like the front corners, it should trap some around 90Hz.



 

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Discussion Starter #73
Here are the new results after putting in the insulation. I had some extra to place above the right subwoofer where there was none.



These were the filters.



The intro to Star Wars EP3 at reference level sounded fantastic but the track lighting was shaking around like a leaf. I will do my best to secure that. We will be replacing the hole in the ceiling where I have taken down the hush box and the projector still is hanging with more Ceilume Ceiling Tiles/Back Panels, and insulation.

The surrounds seem to have improved but it looks like my single 2" 2X2 panel that I forgot was in the corner next to my right surround is helping more than treating above the ceiling helps.

Surround right


Surround left


Center
 

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Discussion Starter #75
That is getting very smooth, you must be impressed with the results. :yes:
I think that I must spend at least a few hours in the HT listening to music and it sounds even better than before. The room sounds less bright than it did now since I have completed putting up the fabric on the rear traps.

In an odd note I found my settings in the pre/pro to be different than I setup last time, or at least wat I thought I set them to. :huh: The subwoofer level was -5 and the mains were not adjusted like I had them. This has happened before that I can remember. I will need to check a manual and see if I can figure out the memory button. It could be I made so many adjustments I forgot.

Right now I would give the sound in the room :4stars:
 

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Discussion Starter #77
There is no cutting of OC 705 required. :whistling: It would help if I could remove the old screen frame which I might end up doing. That would allow it be inserted with a friction fit.



Here is one of the rear traps being built. I had an espicially difficult time with the left side because my stapler began to jam no matter if I put in newer staples or not. It was also difficult on the left side because the jigsaw is missing the peice to hold it straight and the angle of the blade was not ideal for cutting angles on that side of the room when I needed to keep the blade angled away from studs. At least the drill is fixed, but we did get a new cordless also. The trim does not match perfectly but it was as close to deep cherry as they had. I am wondering if I could not spray a transparent red over it to make it look cherry. I have never stained before but I know that it is difficult to match a stain. Maybe I should not worry about that. At any rate I got them cut pretty close to being flush but I'm sure I will do better without having to worry about the straight cuts and fabric on the next one. I might need more trim to finish, and I am debating whether to cut my losses and return what I have then stain some instead. I had not realized that the cut edges of the fake wood would look like unpainted cardboard.

 

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Discussion Starter #78 (Edited)
I had to do more corrections. Everytime I change something I have to go back and change 10 times as much.

  • Took the kraft paper off insulation in the stage & uncompressed it some
  • Moved more 2" panels over the stage
  • Covered the front wall with OC 705 2"
  • Moved the Pillar Traps away from the corners some & removed insulation under them
  • Moved speakers away from the listening position inches
  • Didn't equalize bellow 50Hz
Hope this looks alright. This is the left speaker.



My right speaker shown in this graph I had to go back and take extra absorption out from behind the speaker that I added inside the cabinet. :whistling: This shows just how sensitive these graphs are to my speakers from around 7' away pretty well.



I fixed that so hope it looks better and more like the left speaker next time I measure.

Here is a new RT60 graph (interpret at your own discretion). The area above 1Khz went down in level after removing the kraft paper and moving the speaker and not just after adding the 6 panels of OC 705, which I had done earlier.

 

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I admire your determination (and energy level!) in getting your room treatments right. You have me thinking about treating my ceiling after all.

In a previous post you mentioned track lighting. What brand/style did you use and do they rattle? I have recessed cans in the ceiling that supplied enough light until I blacked out the ceiling. Some track lights around the room perimiter would help.
 

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I would strongly recommend against track lighting - exactly for the reasons that are being described here. Just their basic design and flexibility (advantages) make them inherently non-rigid. I had track lighting in one house many years ago and whenever I'd get the sub up and moving, not only would I get buzzes and rattles, I'd pop bulbs unless I used the rough service ones.

Bryan
 
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