I have some special subwoofer cable that works very well, I don't have much and I can't get more! It is not flexible at all and a pain to use(very rigid), similar to romex-though much higher quality. It has 4 wires inside its sheath, which has a foil layer around it, very welly built cable. It gives a super sharp, dry snap when bass hits that I have never experienced with any other cable that I have tried before. The dealer I got it from disappeared, with out a trace! No clue what happened to him, but this stuff is great and I only have like 15ft of it, if you want to try it out let send me an email and we can discuss it a little further. Cheers,
Tim