It can sound really different either way. The guy who designed my speakers, Alan Yun (Silverline Preludes), told me they (specifically the Preludes) sounded more "coherent" with high quality single wire so, of course, I ignored him and bi-wired 'em anyway. Turns out he was right, and I learned from listening what "coherent" sounding speakers actually means...they really do sound much more "organized" tonally in my system with single wire (AQ Type 8). It has to be speaker/system/personal taste specific, and hey, I'm lucky he answered the phone the day I called Silverline.