Hi. I have the Denon AVR-787 receiver which has a single output jack for a subwoofer. I was just given a Polk Audio receiver which has Red and White RCA inputs. I don't have a cable so I pickup a set of basic RCA cables...red and white plugs on each end. I plugged just the red plug on one end into my receiver's single subwoofer output and then plugged the red and white plugs in at the subwoofer inputs. But I get virtually no volume from the subwoofer. I made sure the receiver was outputting to the subwoofer, crossover is at 80hz, and I also made sure the volume on the back of the subwoofer was turned up. Still I get virtually no volume from the subwoofer. Can I use the cable I'm attempting to use or Do I need a special cable (what would the cable be called)? Any help would be greatly appreciated!!!