As wingnut mentioned, it is sometimes recommended that you avoid coiling or looping excess lengths of speaker cable - this is because of a fear that the coil will act as a sort of rudimentary inductor and thereby change the overall inductance of the speaker cabling. I don't know how measurable that change would be, either electrically or audibly, but it should be [i]very/[i] small (approaching nil). As for folding a cable, you obviously don't want to pinch it badly enough to damage conductors inside the cable.