I spent most of the last week dealing with positioning and testing 3 subwoofers as the culmination of previous testing and moving. I'm posting this with the hope it can help others achieve similar results, and this is before using calibration software like Dirac etc.
I've got a pair of 12" Sumiko S.10 subwoofers and an older 10" Rel. I used REW and a miniDSP 2x4HD along with a UMIK-1 microphone for doing this.
The Microphone Crawl
I did NOT do the normal sub-crawl. I did the mic-crawl. I placed my small down-firing subwoofer upside down at the MLP. Then used REW which has a couple valuable tools, RTA and Generator. Generator will play pink noise at whatever range of frequencies you want, and Real Time Analyzer will "record" the noise and make a plot in real time. The reason this works so well is due to the mic being able to "hear" all the frequencies and REW turning that info into something meaningful. I scoped out my entire great room this way. Whilst dangling the mic and swinging it around an area the size of a subwoofer, I recorded for a short time until the curve materialized then stopped, then repeated this in spot after spot after spot, etc. The RTA will record the peaks so when the curve slows down its progress to almost no change then it's time to stop and move on. Over the course of 20 minutes I covered the whole space and didn't have to bend over. Once I saw what was happening in different areas I got a handle on seeing how the curve changes and it became more predictable as time went on.
Once I found all the interesting spots, I put triangle casters under the feet of the heavier subs to be able to move each of them easily. If the sub was on a rug I left the casters on, but if on the wood floor I would remove the casters once in the right area and just shove the sub from there. You could always use rags under the feet to be able to slide the sub around.
Attachment 010012-PLAN is the layout (and this version happens to show the first real successful sub combo). The spots that showed promise from the mic crawl are shown in yellow CAP letters.
The first day of real measurements I tested Positions A with S2 and B with S1, individually, then together. Not great.
The next day I tested all the spots in the dining area and ended up putting S1 in Position D, and kept S2 in Position A, and put S3 in Position C. This wasn't horrible, but had a large dip that I couldn't reduce.
Test day 3. I moved S2 to H and I, and everywhere within 8' of the wall and ended up using H. So this was S1D, S2H, and S3C. This was really great!
Attachment 010012-3-S1D-S2Hinverted-S3C is the result of S1D, S2H, S3C with no PEQ, no crossover, no Dirac or other calibration. In the miniDSP I only used Delay, Inverting S2H, and Subwoofer Gain to adjust.
The day after this result, and after knowing a little more about what can be done to improve things and thus also understand more about what I wanted to get from each subwoofer, I checked a little more and found two more spots that improved upon the previous results: K and L.
Attachment 010031-PLAN shows the new Positions for S2 and S3.
Attachment 010031-S1K-S2Hinverted-S3L is the final plot. This result shows that central peak at about the same level, but all the frequencies below and above have higher output by 2-3dB vs the other plot, and that narrow deep dip is gone.
I found that adjusting the delay can be quite tedious. So I came up with something that got me in the ballpark quicker. I used Generator and RTA while adjusting the delay and looking at the RTA screen. It needs refreshing a few times, but it's really quick doing it this way.
I've got a pair of 12" Sumiko S.10 subwoofers and an older 10" Rel. I used REW and a miniDSP 2x4HD along with a UMIK-1 microphone for doing this.
The Microphone Crawl
I did NOT do the normal sub-crawl. I did the mic-crawl. I placed my small down-firing subwoofer upside down at the MLP. Then used REW which has a couple valuable tools, RTA and Generator. Generator will play pink noise at whatever range of frequencies you want, and Real Time Analyzer will "record" the noise and make a plot in real time. The reason this works so well is due to the mic being able to "hear" all the frequencies and REW turning that info into something meaningful. I scoped out my entire great room this way. Whilst dangling the mic and swinging it around an area the size of a subwoofer, I recorded for a short time until the curve materialized then stopped, then repeated this in spot after spot after spot, etc. The RTA will record the peaks so when the curve slows down its progress to almost no change then it's time to stop and move on. Over the course of 20 minutes I covered the whole space and didn't have to bend over. Once I saw what was happening in different areas I got a handle on seeing how the curve changes and it became more predictable as time went on.
Once I found all the interesting spots, I put triangle casters under the feet of the heavier subs to be able to move each of them easily. If the sub was on a rug I left the casters on, but if on the wood floor I would remove the casters once in the right area and just shove the sub from there. You could always use rags under the feet to be able to slide the sub around.
Attachment 010012-PLAN is the layout (and this version happens to show the first real successful sub combo). The spots that showed promise from the mic crawl are shown in yellow CAP letters.
The first day of real measurements I tested Positions A with S2 and B with S1, individually, then together. Not great.
The next day I tested all the spots in the dining area and ended up putting S1 in Position D, and kept S2 in Position A, and put S3 in Position C. This wasn't horrible, but had a large dip that I couldn't reduce.
Test day 3. I moved S2 to H and I, and everywhere within 8' of the wall and ended up using H. So this was S1D, S2H, and S3C. This was really great!
Attachment 010012-3-S1D-S2Hinverted-S3C is the result of S1D, S2H, S3C with no PEQ, no crossover, no Dirac or other calibration. In the miniDSP I only used Delay, Inverting S2H, and Subwoofer Gain to adjust.
The day after this result, and after knowing a little more about what can be done to improve things and thus also understand more about what I wanted to get from each subwoofer, I checked a little more and found two more spots that improved upon the previous results: K and L.
Attachment 010031-PLAN shows the new Positions for S2 and S3.
Attachment 010031-S1K-S2Hinverted-S3L is the final plot. This result shows that central peak at about the same level, but all the frequencies below and above have higher output by 2-3dB vs the other plot, and that narrow deep dip is gone.
I found that adjusting the delay can be quite tedious. So I came up with something that got me in the ballpark quicker. I used Generator and RTA while adjusting the delay and looking at the RTA screen. It needs refreshing a few times, but it's really quick doing it this way.