The sub is on the opposite side of the room. It basically is setup like this. 12x15 room
X = Tank
S = Speaker
_ = floor
[S_____B______X S]
[_____ e______ X ]
[______d________]
[_______________]
[sub____________]
[_______________]
[S______tv______S]
And the sub isn't set that hihg, maybe about at half, it's powered but the level is at half.
I will tell you right now, that being in the corner, the tank is getting the biggest amount of bass.
turn it up and go stand in that corner, you will notice the bass either increase ALOT, or almost vanish.
Ive done some extensive audio stuff when I built my sub that cracked my basement windows at my old place.... and your corners, are the hotspots.