Speaker cable geometry question

Spacing wires apart will obviously reduce wire-to-wire capacitance with some increase of the wire inductance (that is more important IMHO).  In addition electrical noise pickup is proportional to the area between wires.  It might not  seem important (since it is output), but output, in most cases in an input to NFB.  There is no right or wrong here.  It all depends on your system, your location etc.

Long time ago I read FAQ by Audioquest on the subject of speaker cable geometry.  They claim that  skin effect, that starts (copper at 20kHz) at gauge 18, affects the sound.  Using multiple insulated strands helps a little, but strands are still in magnetic field of each other.  Better solution is to arrange strands in a tape fashion, so that magnetic field of each strand would affect only neighboring strands.  Better yet is to lightly twist this tape on a round hollow core.  Twisting reduces pickup from electric and electromagnetic fields.  That is how my Acoustic Zen Satori cable is constructed.  The problem is that this hollow core design makes this cable over 1" in diameter (and I have shotgun cable = 2x1").

I'm surprised that they consider skin effects in audio.  Perhaps it slightly affects harmonics at 20kHz (that I cannot hear anyway).  Also, any increase in cable impedance at 20kHz is probably much less than increase in cable's inductive impedance, not to mention that speaker is most likely "inductive" at high frequencies increasing its impedance (less of the load).

We can always find some plausible explanation for any cable construction, but is it audible?  The more I try to understand it the more it is magic to me.  Long time ago I had inexpensive Audioquest Indigo.  It was OK, but sounded a little thin in the lower midrange.  Acoustic Zen Satori lower midrange is much more pronounced.  Male voices have more "chestiness", cello has deeper/fuller  sound etc.  Cable is a filter (like everything else in audio system), but I cannot imagine what kind of filter would improve lower midrange only.  Voice have some added smoothness/silkiness to it - how can I express cable "silkiness" as LCR?

Cables don't directly change midrange only, but moving speakers to change wires often does.

Speakers are in the exactly same marked location, angle etc.  Nothing changed in the room.