Help with multiple sub placement - AVS Forum
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post #1 of 3 Old 03-10-2012, 01:44 PM - Thread Starter
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Trying to find the best compromise in subwoofer locations. I am trying to best locate 2 subs in my room, one is a paradigm w/ PBK options and the other is very old very basic 12" sub that I built for a car system around 15 years ago but works and sounds much better than expected. (see back story for more detail)

The subs are currently in opposite corners, and the room is evenly filled with smooth clean bass. However I know im giving up some low end extension on the Paradigm sub in its current location. Overall this seems like an improvement as I was noticing localization with just one sub. Any comments from the more experienced in where to put the subs to keep the lowest extension and the best, most even, bass?

In reference to the picture, room is 14x20 and the picture is basically to scale. Red squares are subwoofer options.

1. hits a major room mode at 40hz and mild null at 70hz, PBK graph drops fast below 25hz. Paradigm sub currently here.
2 hits a big room mode at 40 but misses the null, PBK graph is flat to below 20hz. I am tempted to put the Paradigm sub here but am worried that I the left side of the room will sound empty...
3. major room gain from 40hz, and major null at 70hz. sounds boomy even after the PBK.
4. is the sweet spot, mild gain below 30hz and basically flat frequency response. Car sub currently here, thinking I will leave the car sub here as I have no way of EQing this sub.
5. Is a pretty mediocre spot, suffers from the mode and null, with just one sub it was very apparent the sub was right beside you.


Back story, I recently got a paradigm monitor sub12, tried several locations and finally settled on the rear right corner as, according to the PBK, that corner has the best acoustics. A bit of room gain below 30Hz but basically smooth and flat. Run the PBK and leave it be for a few weeks. I swear that I can tell the bass is coming from that corner and start thinking about a second sub... It then dawns on me that I built a car audio sub something like 15 years ago, I am using the 100 watt rms amp from my very crappy HTIB sub to drive an ancient phoenix gold 12" driver, to my surprise its working FAR better than expected. In any case the car box was port tuned to 35hz and it didnt sound great below that, so I blocked the port and its very good for what it is. I put the car sub in my good corner and my paradigm sub in the opposite corner and rerun the PBK. Listened to some music and watched tron: legacy, all in all pretty good smooth and even bass. HOWEVER in this particular corner the monitor sub gives up in the low 20hz, where on the other side of the TV it will PBK flat to below 20hz. It would seem to me that opposite corners will be the best for filling the room, or would I get the same effect on the other side of the TV (spot 3). Comments?

Of course I will try it, just dont have the time for a little while.
LL
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post #2 of 3 Old 03-11-2012, 10:34 AM
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I tryed to read up on the PBK. Is that unit capable of reading sweeps like REW and OmniMic ? ...or does it room correct
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post #3 of 3 Old 03-11-2012, 11:49 AM - Thread Starter
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The PBK is a calibrated USB mic, sends / reads sweeps via USB to paradigm subs and room corrects. The PBK software gives a nice display of the sweeps.

I can use the PBK mic with REW but havent had luck getting REW to recognize the calibration file. So I dont know how much use that setup will actually be.

I can also do a "quick measure" with the PBK, which sends, reads, and displays sweeps. I THINK i could turn the gain right down on the paradigm sub and send send sweeps via REW to the other sub to get an accurate reading from it.
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