If I have three subs per side and want to use one backward/reversed phased/delayed for rear cancellation, is it best positioned side-by-side in the middle, in the middle stacked vertically, or on the bottom stacked vertically? Or does it matter at all?
I have tried the setup pictured live and found that there seems to be just a little more in front. But I didn't really find that much cancellation in the rear. I'm hoping to spend more time experimenting with these setups but as I don't have any measurement tools like Smaart (and don't really have the know-how to use them) it will be all by ear.
It depends on where you want the cancellation notch to be.
If you want it straight to the rear-then vertically stack.
If you want it a little bit to one side or the other, you put them side by side.
YES, it does make a difference.
There should have been a good bit of reduction in the rear.
Did you have the proper delay-polarity set on the proper cabinets-along with the proper spacing?
It takes all three setup correctly-delay-polarity and spacing to get the idea to work.
Were there any boundaries nearby? That will start to throw things off a bit.