Yeah, that's a really tough room for audio; you're right that it's best to use as many subs as you have room for, though they don't need to be so big, i.e. had you asked at the beginning I (we?) would have pointed you to Dr. Geddes multiple woofer papers and IME instead of a single tube sub filling corners, use 'infinite' subwoofer arrays that turns the room into more of a uniform particle density like in a speaker box, i.e. much muted room modes/'immersed' in the (sub) bass.
Unfortunately, unless you can get most of your investment out of the existing subs, guessing a too costly renovation.
Unfortunately, unless you can get most of your investment out of the existing subs, guessing a too costly renovation.
Having both subs together might be less than ideal. Try this procedure...
Measure with your mains playing, no subs, no DSP in the bass region, don't cross your mains... Look at the peaks and dips at the low end (below 100Hz, maybe 200Hz).
Now, put one sub somewhere and measure with the three speakers playing. Set the sub level so the average bass level is the same as before. They should share with the mains, not overpower them.
You'll have a good result if each dip from the first measurement has gone up at all, and each peak has gone down at all, and the average level stays about the same. If it does the opposite where the peaks and dips all get worse, change the sub polarity and try again.
A bad result is if some peaks/dips go the wrong way and some go the right way. In this case, move the sub somewhere else and try again. Mess with low passing the subs between 100-200Hz as needed but don't highpass the mains. You might try (simply) adjusting delay on the subs only, but don't try to time align.. just look at the modes.
Your goal at this stage is to find the location, level and low pass of the subs that works together to improve the original response from the mains alone to make it more flat. Soon you'll get a feel for the abilities and limitations of this process, so settle on the best location you can find then continue on with the second sub.
The second sub should probably not be higher in level than the first. You are now measuring with all four speakers playing, looking for an even flatter response. Sometimes one sub is better lifted off the floor.
When this is good, it is time to equalise what remains with your DSP.
Measure with your mains playing, no subs, no DSP in the bass region, don't cross your mains... Look at the peaks and dips at the low end (below 100Hz, maybe 200Hz).
Now, put one sub somewhere and measure with the three speakers playing. Set the sub level so the average bass level is the same as before. They should share with the mains, not overpower them.
You'll have a good result if each dip from the first measurement has gone up at all, and each peak has gone down at all, and the average level stays about the same. If it does the opposite where the peaks and dips all get worse, change the sub polarity and try again.
A bad result is if some peaks/dips go the wrong way and some go the right way. In this case, move the sub somewhere else and try again. Mess with low passing the subs between 100-200Hz as needed but don't highpass the mains. You might try (simply) adjusting delay on the subs only, but don't try to time align.. just look at the modes.
Your goal at this stage is to find the location, level and low pass of the subs that works together to improve the original response from the mains alone to make it more flat. Soon you'll get a feel for the abilities and limitations of this process, so settle on the best location you can find then continue on with the second sub.
The second sub should probably not be higher in level than the first. You are now measuring with all four speakers playing, looking for an even flatter response. Sometimes one sub is better lifted off the floor.
When this is good, it is time to equalise what remains with your DSP.
'Infinite' corner arrays, i.e., one that's at least ~0.707x a room corner's height, centered vertically:
One pro's infinite array
Infinite line array analysis
Yes, hence my response. 😉
Side rooms act as huge bass traps, so really depends on measurements at the listening position as to whether it's beneficial or not. If you partition it, then the door way makes it a band stop filter that will put a huge null somewhere in the (sub) bass.
Like I said, a really tough room for audio
, though corner arrays can swamp a room with no floor/ceiling bounce as a side benefit, but if not wanting the extra effort at this late date, then the more Monoliths around the room the better 😉 per Dr. Geddes multiple woofer papers.
The avsforum.com bassheads go by 25m/s. I personally try to get under 10m/s. I think original WinISD is 16m/s.