You mentioned something I should have pointed out. The sound engineer was indeed a fill-in guy. In the past, the sound has been excellent, and very, very loud, but comfortable if you're wearing earplugs.
At this show, the sound was even louder than normal, and although I was wearing my foam earplugs, I kept subconsciously reaching up to be sure they were still in properly because it was so loud. The sound in the room was not necessarly bad, but not as good as when the usual engineer is working the board.
The vari-phase rotator in RX2 corrects the shape/appearance of the wave form, but I could not detect any audible change in the sound.
Do you hear specifific frequencies that need attention?