Why do digital cables sound different?

Megasam: yes, all cables have some effect (i.e., error) on the signal waveforms passed though them. However, the beauty of digital communications is that, with proper system design, these analog errors can be ignored or removed at the receiving end. That is, errors are NOT necessarily additive in a chain of digital components, as they are in analog communications (i.e., in analog, the SNR must get worse with each additional component in the signal chain). Example of how errors may be removed in the digital domain include error control coding and reclocking of buffered data. A favorite question of mine is "how can this be so?". When faced with claims of audible differences between digital cables some possible explanations that come to mind are a) placebo effect, b) a substandard cable has been replaced with one of proper bandwidth and impedance (and once it's "right" it can't get "better" in a digital system, or c) some sort of weird equalization of the digital waveform is going where the distortions of a particular cable are being used to compensate for distortions of poorly designed digital data transmitters and receivers in the transport and DAC. In a digital communications system, these kinds of effects are sometimes called ISI, or intersymbol interferance. To me, case c) is not an acceptable state of affairs and cable and audio equipment manufactures should be better serving us.

First - the digital datastream carried on a coax connection is an analogue signal, albeit used to represent 1's and 0's. Second - I have never seen a signal coming out of one of these cables on a scope that is a perfect square wave. Third - lack of perfection in the square wave means jitter. Fourth - jitter produces harmonic distortion in the output of the DAC, different forms of jitter distortion producing different harmonic signatures - some sounding soft, some sounding harsh. Fifth - I have never heard or measured a reclocking device (including the Genesis Digital Lens) that does not reveal some of the jitter distortion created by upstream cables and components. And what is more important is that digital cables do sound different, provided of course you have a high resolution system and sensitive ears. I am intrigued however about the observed phenomena of a cable's sonic signature when used as an analogue interconnect, being present when used as a digital cable. I have heard this too, and with cables other than Kimber, and I reject the placebo argument in the context of how I test components. I find this one harder to explain and can only surmise that we cannot look at interfaces between components as separate systems, and that each interface may leak artifacts of itself into other parts of the total system. The active devices that buffer interfaces are meant to deal with this, but perhaps no real world electronic part works exactly how it is designed to work?

For some reason all of these explanations are never good enough for some people. This topic inevitably leads to a long debate. Science tries to explain an experience and often falls short. All I need to know is that I tried 5 different coax cables and they all sounded different. One was consistantly better than the others, and I bought it. Anyone who can't hear the difference needs work on their listening skill.

Hear Hear.