I tried doing some searching to answer this question...I'm sure its covered somewhere...alas.... I "think" I more or less understand what phase adjustability is, but it sure would be nice if someone had a link to "Phase for Dummies". Why do most plate sub amps have adjustable phase tuning and pro amps do not? It phase adjustment something only needed down in the low hz area and thus skipped by pro amps? Or are pro amps so well designed they just don't need the ability? Taking, say, an SVS sub for example, all their powered subs have a phase knob, but the high end pro amps for the unpowered models (Samson,Crown) don't. I'm missing something, I'm sure. thanks in advance!