Simple question, or is it...

Huh? Then maybe you can tell me if this is where all those guys get their info. 
An excerpt from Wikipedia,

Coaxial cable[edit]Poynting vector in a coaxial cable, shown in red.

For example, the Poynting vector within the dielectricinsulator of a coaxial cableis nearly parallel to the wire axis (assuming no fields outside the cable and a wavelength longer than the diameter of the cable, including DC). Electrical energy delivered to the load is flowing entirely through the dielectric between the conductors. Very little energy flows in the conductors themselves, since the electric field strength is nearly zero. The energy flowing in the conductors flows radially into the conductors and accounts for energy lost to resistive heating of the conductor. No energy flows outside the cable, either, since there the magnetic fields of inner and outer conductors cancel to zero.

Mass? I haven't been to mass in decades.

Uh yeah OK, you've lost me.  coaxial cables are transmission lines. I don't  think to many people use them RG6 or RG59 as speaker cables or interconnects I suppose they could. 

Poynting vectors apply to any conductor where there is an EM wave, as in any cable or power cord. No? I don’t particularly care about Poynting vectors as I don’t think they completely explain the audio signal in wire or “directionality“ or how the audio signal is affected by vibration, among other debatable audiophile topics. I suspect Poynting vectors are more useful to skeptics.

OK, you're beyond me. It has to do with flow of energy in EM field or something but I don't see how it has anything to do with the question of what's an audio signal and what's it travel through.