Do Costly XLR Cables Make A Difference?

I honestly do not know, @holmz: I never did the comparison in a blind A/B setting, let alone did I perform any measurements. I just re-iterated what I had read in various blogs and articles written by specialists (I, on the other hand, am an organic chemist and not an electrical engineer). My only personal reference would be swapping insulated Mogami XLRs for "naked" Anticable ones; and as I have said: the acoustic differences were minor (I got the Anticables for a basement discount, btw). But I must say nevertheless: reading deeply into the physics behind cable design and architecture was quite humbling. There is a lot more going on, then just sending current through a wire, when it comes to a veracious reproduction of highly modulated and complex audio signals, that's for sure; and the scientist in me thinks there might be still effects out there which we do not know about and hence do not know how to correctly measure and quantify. On the other hand, though: the final link in the event chain is our brain, and just before that our innate mechanism to transform minute tree-dimensional air pressure variations into electrical signals. And quite obviously, the fidelity of this mechanism suffers from age. In other words, whatever objective truth there might be behind what we read about cable X being "better" than cable Y, it might just no longer be audible to us once we finally got the financial means to embark on the serious quest for the audio Grail.

Thanks @reimarc .
 

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There is a lot more going on, then just sending current through a wire, …

It is more like sending the electric field around the wire, then current in the wire for an IC.
A speaker cable has more of the current. 

Cotton and “naked” are more affecting the field and how it propagates. Whether we hear much of what is happening is uncertain, but it could get pretty nuanced.

I got some cotton ones to try out.

@reimarc - What's most interesting is that even if we could measure every aspect of cables and audio equipment in general, listener preference would still trump.  My ideal would be to meaningfully correlate measurements to sound signatures so that it would be possible to use the measurements to make at least an educated as to whether I might appreciate the product.

I would agree with Whipsaw.  If you've got a good 2k cable, spending a lot more may only yield a very small improvement, if any is even noticeable. You can spend thousands more chasing rainbows. If you're going to make a leap, go much higher and buy Audioquest Dragon.  If you don't hear an improvement, lesson learned.  If you do hear an improvement, stop there. Don't be tempted to go into the stratosphere of Crystal Cable (despite what Jonathan Valin says in The Absolute Sound) or top of the line Siltech unless you're a Saudi oil sheik and don't care.

For holmz: check this website for cotton-insulated wires: https://www.vhaudio.com/unicrystal-occ-silver-wire.html

BTW: the way I understand it, the electromagnetic field around the conductor arises the moment it gets connected. What we call the 'signal" is actually a disturbance of this field traveling along the conductor at near-light speed. However, the material-dependent impedance of the conductor is responsible for the time-aligned transmission over all frequencies; hence the "smearing" of the signal at higher impedance. This part is still puzzling me: if the event takes place around the conductor and not through it, how can its material make a difference? Or are some aspects of the field dependent on it? But again, I am not an electrical engineer or a physicist.