I have a similar setup where there is a couch 2' in front of my left front speaker. Before volume balancing, the whole image was shifted over to the right side. I found I had to up the left side volume by about 2db to compensate and that centered things more.

I havn't yet checked if/how it affects imaging.

Fred

-------
Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!