I bought a Pioneer VSX-D514 today. I used to have a Sony DAV300 all in one DVD/Amp thing, so for now, I'm just going to use the speakers and cable from that. Here's the thing. The end of the cables had sony specific connections on them. I chopped them off so the bare cable fits into the new amp. However, I have no way of knowing which is positive and which is negative. They're marked grey and black at the speaker end, so that's fine, but at the other end, I've no way of knowing. I can't trace the cable back because they run under the floorboards. They seem to work fine know matter which way I plug them in, so what I want to know is: - Is there a difference in sound quality if I have the negative/positive mixed up? - Can I damage the speakers or amp by having them mixed up? - Is there any way of finding out which is positive/negative without having to pull the cables up? Thanks in advance.