Hi, I've plugged my D-Box sub into my Harmon Kardon AVR125 reciever via the sub in on my reciever and out via a 2 headed RCA cord to my sub. In other words, my reciever only has a single RCA input that I have plugged my powered sub into through a red and black RCA cord due to the fact that my sub out has dual outs (right and left?). I have been getting this horrible humming and feedback coming from my sub now that's getting worse and will only stop once I've stomped on the floor. What can I do? i think it's the 2 rca outs from the sub to the y connector to my stereo possibly? Help, my ears hurt.