Move the subs out of the corner and try something like this..

Rather than stacking, you can also get a in-wall sub for either sub 3 or sub 4..and mount it in the ceiling at the same lengthwise/widthwise location in image above. Ideally, you would want sub 3 at 1/4 height and sub 4 at 3/4th height and so on.. The idea is to remove some heightwise nulls by mounting a sub at ceiling height...If you stack expensive subs all the way to the ceiling, your wallet might lose some of its rotundness.
@ozzy wrote
I have 4 subs, placed in the corners of the room. But I wonder if stacking 2 in the front would be better?
Anyone have an opinion on this? They are heavy, so to stack might be difficult for me.
ozzy

