Why a mixer with a 1680? I record full bands, and with only 8 channels of record at a time, I need to submix toms to gain a record channel many times. Kick, snare top, snare bottom, 2 rack toms, floor tom 2 overheads = 8 mics. submix the toms, and gain a channel for bass, submix the 2 snare mics...