Jim (Jea48), Jc4659, and Kijanki, thanks very much for your kind words.
Jim (Jea48), I’m not sure if your most recent post is suggesting that I try to explain why Geoff’s comment is incorrect, or that I refrain from doing so to avoid having this heretofore constructive thread go downhill the way the recent thread on wire directionality has. But I’ll assume the former, perhaps incorrectly.
Geoffkait 8-24-2017
If the audio signal travels through the *dielectric* and not (rpt not) through the metal conductor I suppose we can throw out the whole skin effect idea, which says most audio frequencies travel *inside* the metal conductor at some depth, with only very high frequencies, perhaps above "audio frequencies," traveling near the surface, I.e., skin. How can audio frequencies travel inside the conductor when the audio signal - the electromagnetic wave - travels outside the conductor?
Geoff, to be precise, skin effect means that as frequency progressively increases above a certain frequency (which depends on the diameter of the conductor), "
current density" (with "current" defined as in one of my earlier posts) decreases to a greater degree at progressively greater depths. That causes a progressive increase in the resistance of the conductor at progressively higher frequencies.
"Audio frequencies travel inside the conductor," to use your words, in the sense that the movement of electrons, at the very slow drift velocity I referred to, is a very small back and forth oscillatory motion occurring at the same frequency or frequencies for which energy is being conveyed in the electromagnetic wave. As the +/- polarity of the applied voltage changes, at a given frequency, the direction of that slow movement of electrons changes correspondingly. (And actually, to be precise, I should say "net movement of electrons," because random movement of some electrons is always occurring to some degree).
In the recent wire directionality thread which you participated in extensively, Jim (Jea48) quoted a statement by Ralph Morrison, a world renowned authority on such matters, and the author of several textbooks, which contradicts your assertion that the electromagnetic wave travels within metallic conductors. That assertion was also contradicted in another thread here by a noted designer of highly respected world class audio electronics, as well as by me and several other technically knowledgeable posters. During the course of my lengthy career and schooling in electrical engineering I have never seen such an assertion ever made by anyone other than yourself. If you can cite a seemingly credible reference supporting your contention I will attempt to explain why it is either incorrect or is being misinterpreted.
Regards,
-- Al
