There is a reason. The digital signal is transferred at a much higher frequency than the audio signals. At these higher frequencies, the output impedance of the transport, the characteristic impedance of the cable, and the input impedance of the DAC must be matched in order to get all of the energy sent by the transport to be absorbed by the DAC. Any mismatch in impedance will result in some energy being reflected back to the transport. This results in standing waves which distort the signal, that is, it is different than what would ideally arrive at the DAC if all was matched. Some of the enrgy is disipated in the output stage of the transport, and some in the cable. There are other cable losses such as dieletric loss and radiation loss that are minimized by a well designed cable. This area of electronic theory is called transmission line theory and will be covered in any book on basic electronic communication theory. This is an ovesimplified explanation, but my point is that this an extremely complex subject that can't be explained by statements like, " I don't see how a wire can make any difference." I taught this subject for 9 years and the more I learned the more I realized how little I knew.
Why do digital cables sound different?
I have been talking to a few e-mail buddies and have a question that isn't being satisfactorily answered this far. So...I'm asking the experts on the forum to pitch in. This has probably been asked before but I can't find any references for it. Can someone explain why one DIGITAL cable (coaxial, BNC, etc.) can sound different than another? There are also similar claims for Toslink. In my mind, we're just trying to move bits from one place to another. Doesn't the digital stream get reconstituted and re-clocked on the receiving end anyway? Please enlighten me and maybe send along some URLs for my edification. Thanks, Dan