I'd of said this, but i assumed he knewGorty,
pandamonk is correct - a corner is a corner is a corner (to quote Ethan Winer) - it makes no difference whatsoever to the room.......
the only thing I would concern myself with (if this is a control room) would be placing them symmetrically within the room - this becaue they will also attenuate some mid and high frequencies as well as low - and those are more directional - and thus matter more to your stereo imagery.......
Sincerely,
Rod
Would the bass trapping be more effective in the front and back wall-ceiling corners over the side wall-ceiling corners or vice versa?