the new Paradigm Servo-15 v2. I am looking for super clean output that extends below 20hz at high volume. I live in Canada and the servo is about 2400 and the ultra is around 1600? a guess. Thanks And if I were going to upgrade receiver ... which of these Yamaha 2500 , Denon 2805, Nad 773. I am using PSB 5t 2b and 9c with a mirage bps-400 sub. Thanks again.