HELP! I am installing some new Polk DB series speakers that I purchased this AM, and none of the old speakers or speaker wires have + or - markings! Can anyone tell me what to look for or how to tell which is positive or negative on the factory harness ends? Any help would be much appreciated! I am changing the door speakers and the rear deck speakers (not the tweeters yet). I would have ordered them from Crutchfield or someone that could tell me but I HAD to buy them from circuit city (it's a long story)