Is there a difference between a typical analog RCA cable and the digital coaxial (such as a subwoofer cable)? I am considering using the coaxial cable in an automotive application for the entire speaker system, but would see no need in doing so unless there would be a significant difference in sound reproduction and shielding of electrical interferences from other systems in the car. I know the coaxial is supposed to be for digital sound reproduction, but I dont think that would be related to CD's unless coded in dolby digital surround, correct? Any help leading my in the way to go would be greatly appreciated.