06-24-11: Johnnyb53Johnnyb53, while your well written post is, IMO, completely correct from a qualitative standpoint (i.e., if quantitative considerations are ignored), as I've mentioned in response to similar posts you've made in the past it is incorrect and misleading quantitatively.
Ideally they must convey all the various signals (which are minute voltage fluctuations) in time with one another (with the challenge that signal speed varies with frequency), keep the amplitude of each accurate, minimize (ideally prevent) signals from being absorbed by the dielectric to be released back into the signal path later, and have near perfect rise time (which requires frequency response somewhere past 1 GHz).
Risetime need only be fast enough to not have audible effects within the frequency range of human hearing. As you know, that is nominally considered to be 20kHz, but even if we apply a huge margin to that figure, 1GHz is still thousands of times faster than necessary.
Furthermore, it is thousands of times faster than the bandwidths of the speakers, the source material, the source component, most electronic components, as well as our ears, so even if cable bandwidth were vastly lower than 1GHz, and cable risetime correspondingly slower, it would not affect overall system bandwidth and risetime to more than an infinitesimal degree.
Finally, I would maintain that for reasonable cable lengths the claimed need for time alignment is speculative at best, as even the audible frequency having the slowest propagation speed (20Hz) still propagates through wires at approximately 5 million meters per second (with the propagation speed of higher frequencies approaching the speed of light). See Figure 2 of this reference.
Regards,
-- Al