To add to DrBarney1’s post (and I agree with his math), it is possible that in some circumstances skin effect in a speaker cable can actually be beneficial. While it will have negligible effects at audio frequencies, as he indicated, it seems conceivable that the resistance rise it causes at RF frequencies could reduce RFI that is picked up by the cable and introduced into the feedback loop of the amplifier (assuming the amp has a feedback loop). RFI that might otherwise have audible consequences as a result of effects such as intermodulation or AM demodulation, that may occur within the amp.
And in connection with that possibility I note the following statement in the article:
Hiraga pointed out that while theoretically the skin effect appears to be negligible for frequencies below 200kHz, subjective listening tests suggest otherwise. Apparently, he started experimenting as early as 1972 with Litz-type speaker cable, which consists of a large number of individually insulated fine wires twisted or braided into a uniform pattern in order to maximize conductor surface area. He substituted Litz wire between an amplifier and an Onken 5000T tweeter and discovered that as the number of strands increased, so did the impression of detail and definition, accompanied by the perception of additional distortion. The obvious conclusion was that one should not shoot the messenger since the Litz cable was allowing more of the message to get through.
Perhaps the "obvious conclusion" that is stated is not so obvious, and instead "the impression of detail and definition, accompanied by the perception of additional distortion" was due to the effects of RFI that I referred to. Those effects resulting in inaccuracies that were subjectively preferable, and were maximized by a reduction in skin effect.
Regards,
-- Al