After procrastinating for six years, I finally caved in and bought a subwoofer for my HT sytstem. I have bought the Yamaha YST-SW215 subwoofer (I live in a small apartment and this sub is perfect and very tame -- no complaints from my neighbors so far). I have a few questions on set up: 1. At what level should I keep the volume control of the sub at? At present I have kept at halfway between the min and the max levels and it seems to sound fine. Is there any correct way of setting this up? 2. My AV receiver (Yamaha RXV795) manual says that the cutoff frequecy for the receiver is 90. So should I keep the crossover knob on the sub at exactly 90 or will it be OK to keep it at maximum? 3. I have used the AVIA disc for calibrating my 5 speakers, but I am not sure how to calibrate the sub, as it is very confusing. Any tips? Thanks in advance.