I have installed a 7.1 in-wall system using a M&S SUM Subwoofer (MU-SUMWR). This is a passive subwoofer with 2-channel/4-wire hookup. I also have a Sony STR-DE698B receiver with a single RCA connection for a monaural subwoofer cable.
My question is, how should I wire the sub to the receiver? I have tried using a Y connector (from the wall plate connecting to the receiver) and soldering RCA connectors to regular 12-guage speaker wires. So far I have had no luck in getting any sound out of the sub.