I searched through previous posts, but didn't get a complete answer to this question. I know that usually you need coax for line-level output to a subwoofer, but my new house came prewired with speaker wire going to the back of my family room, two pairs for each side (left and right surrounds). Since I don't biwire my speakers, I was wondering if I could use the extra pair of wire so that I don't have to put extra cables down to my powered Energy Take 5 subwoofer. In other words, is there a way to solder on RCA plugs onto a pair of plain speaker wire to carry line-level output, or does that not work at all? I cannot use speaker-level outputs to the subwoofer, because there aren't enough wires to carry the signal back to the front speakers and simultaneously wire the surrounds. Equipment involved: Denon AVR-1700, Energy Take 5 speakers and powered subwoofer, prewired family room, and one Monster Cable subwoofer cable now useless because its not long enough.