Over the holidays I purchased a new amp Yamaha RX-A2000. I was using an Onkyo TX-SR 806 before and all worked well. Anyway I hooked up the new amp along with 5.1 surround setup & all 7 components I have all HDMI thru amp. My speakers are as follows 2 Cerwin Vega CLS15 for the front 1 Cerwin Vega CLS-6C center channel, 2 Cerwin Vega CLS-6 rear speakers and 1 Cerwin Vega CLS-12s sub. I double checked all connections and and ran the speaker test and it was saying woofer 1 out of phase all the time which also cut 90% of the bass. I could not figure it out as I never had this problem with the other amp using all the same connections. Finally just for the hell of it I unplugged the sub from the powerbar I was using and plugged it into the back on the surge only side of my APC smart ups 750SMX and that solved the problem right away. I just can't figure out how moving the plug from one power source to another would have anything to do with it especially since it was working before the way it was on the other amp. Im just happy its all working great now, but maybe someone out there can tell me how it would work that way.