Compuserve's CEAUDIO forum has been buzzing in recent weeks about audio cables. The subject even spilled over into an April meeting of the New York chapter of the Audio Engineering Society (see Wes Phillips's report in this month's "Industry Update"). Nearly two decades after Polk, Fulton, and Monster Cable raised our collective consciousness about the differences cable choice can make in an audio system, the debate still rages between audiophiles and some members of the engineering community. "High-priced tone controls" is how some engineers dismiss the subject of cables, while admitting that they can sound different. Other engineers adopt the "Hard Objectivist" line that if there are differences to be heard between cables, differences in the lumped electrical parameters of resistance (R), inductance (L), and capacitance (C) are all that are required to explain such differences.

I have heard differences between cables ranging from the almost nonexistent to the obvious. The only physical difference between AudioQuest Clear and AudioQuest Sterling speaker cables is the conductor: high-purity copper in the former, high-purity silver in the latter. Yet the improvement in low-frequency definition offered by Sterling is so large that it might almost be audible in a blind test :-).

In my view, RLC advocates take too simplistic a view of audio-signal transmission—there are other factors that affect a cable's electrical performance. The first three I list are properties of the cable itself; the second three are properties of the system in which the cable is used. (I'm sure there are more.) Yes, these are all secondary effects, but if R, L, and C are the same (not that they often are), what else is left?

• A decade ago, Malcolm Omar Hawksford of the University of Essex in the UK derived from first principles the conclusion that there is an optimum conductor diameter for audio-signal transmission (see "The Essex Echo," Hi-Fi News & Record Review, August 1985, [reprinted in revised form in Stereophile, Vol.18 No.10, October 1995]). I've yet to see a refutation or even any discussion of Professor Hawksford's conclusions, but perhaps coincidentally, many of the "audiophile" cables tend to use conductors of this diameter.

• As an electrical field can't exist in a conductor, and as the audio signal represents a varying electrical field, it must travel in the dielectric medium surrounding the conductor. The primary effect of the dielectric is to reduce the speed of transmission, though this remains a significant fraction of the velocity of light. But as a cable is nothing more than a stretched-out parallel-plate capacitor, and the adverse effects at audio frequencies of using a sub-optimum dielectric in capacitors have been well-documented, isn't it reasonable to suppose that the dielectric can't be ignored in audio cable design? Certainly the best-regarded audio cables use "well-behaved" dielectrics.