Of course length matters, but you won't hear a significant differnce with the lengths in question. The speed at which electricity propogates thru the conductors has less to do with what's going on....than does the cumulative insertion losses due to capacitance, resistance, and the various types of inductance and reactance. ALL OF THESE increase with longer runs of ANY cable (interconnect or speaker cable). This cannot be avoided, it's just basic physics. THERE'S NO GETTING AROUND INSERTION LOSSES, but the difference between 8 ft and 12 ft is nothing to worry about. The differences in "sound quality" would be radically less than, say the differences heard going from one manufacturer's cable, to another's.
