Is there something to listen for when adjusting phase? If I stand behind the subs and adjust the phase, the bass output from the sub is higher the closer to zero I go. Seems to move the bass towards the speaker with the phase setting nearer to the middle or 90 degrees, or it sounds like less bass coming from directly behind the subs. My old setup only had 0 and 180 degrees and I set it at 0 which had the most output.