Well... My 722 is gone so I'm on the r09... I ran split mk21's stage lip/on stage last night, mk21 > aerco > r09. This band is typically very loud up front. I ended up running the aerco at 0dB gain and the r09 at trim setting 8. Final peaks were -4.8dB. For anyone considering an aerco with a min gain of +20dB, this might be something to keep in mind.