Help! I just bought an Energy 5.1 speaker set with subwoofer. Being ignorant, I had an electrician run speaker wire through the walls to all speakers. Now I see the subwoofer is expecting an RCA cable to the Sony AVR subwoofer output. Can I use two RCA connectors from Radio Shack to terminate both ends of the speaker wire? I'd connect the positive to the center plug potions for both ends. Would this work?