I'll echo the above postings about first, turning around at the LP and listening... then proceed with the wire swapping....
THEN not only windows but openings to the room will allow for a suck out to whatever side the opening is, especially if it's close to the speakers. I have two openings, one to either side of the room. Though the one on the left (facing the speakers), is closer to them, so that side has a bit less the impact, that the right side has overall.
Past that there is one other item of note... the player. TT stylus alignment and/or the laser in the CDP could be off.
I say that because I went nuts trying to adjust my room, system, and my sinuses which affected my hearing... and come to find out the laser in my cdp was going out. I've since had it replaced with a new drive/laser sled, and now all is far, far, better. My CDP issue was intermittent so it did drive me nuts for some time. well that and my sinuses.