I have an older SONY 750w system and I've having trouble with the sound quality. Sometimes you can't hear anything out of 1 or two of the speakers. When I use the systems "test tone", some speakers will be hard to hear (low sound level, even with the volume up) or a different tone then the others. The are sometimes not the same speakers. It seems one will work great one day and the next time it won't. Does anyone know what might be causing my audio problems and can you please offer your suggestions to help me troubleshoot and fix it? Also I Changed the gauge of the wire to the thickest wire at HomeDepot a while back. It's about the same thickness as lamp wire. Should I go back to the thinner wire?