My guess is that you're getting bass reinforcement between 80ish and 150ish cycles from the left corner and none on the other side since there is no corner. This may well be audible since it can generate lots (app 12db in my room, relative to 80db) of excess energy in this frequency range which is vaguely directional. Any floorstander with enough bass output will create the same frequency response hump, so if this is indeed your problem, that's not the answer.
A $350 bass buster (or app$450 ATC bass trap) is the best solution. These are hemholtz resonators tuned to absorb energy in the octave above 80hz (this is a very common problem). I'm told the ATC version allows some "fine tuning" of the active range. BTW, even if this doesn't solve your stated problem (left leaning sound) you'll probably be very happy with the overall improvement in sound. I sure was.
Good Luck,
Marty
A $350 bass buster (or app$450 ATC bass trap) is the best solution. These are hemholtz resonators tuned to absorb energy in the octave above 80hz (this is a very common problem). I'm told the ATC version allows some "fine tuning" of the active range. BTW, even if this doesn't solve your stated problem (left leaning sound) you'll probably be very happy with the overall improvement in sound. I sure was.
Good Luck,
Marty