Ethernet Cables, do they make a difference?

It seems to me that what has been largely overlooked in this discussion (with the exception of the brief post by Markalarsen) is the fact that 100% of the energy of an electrical signal, especially one that as in the case of Ethernet contains spectral components at very high RF frequencies, does not necessarily go only where it is supposed to go. Experienced designers of high speed digital circuits (of which I happen to be one) will recognize that.

And given that a number of members here who are highly respected and highly experienced audiophiles have reported finding that the choice of an Ethernet cable can have significant sonic consequences, I offered the following hypothesis in the "Most Important Unloved Cable" thread that David_Ten linked to in his post early in this thread:

Almarg 3-27-2017
Most likely what is happening is that differences in the characteristics of the cables, such as bandwidth, shielding, and even how the pairs of conductors that carry the differential signals are twisted, are affecting the amplitude and spectral characteristics of electrical noise and/or RFI that finds its way via unintended pathways to unintended circuit points "downstream" of the ethernet interface in the receiving device. "Unintended circuit points" may include the D/A circuit itself, resulting in jitter, and/or analog circuit points further downstream in the component or system, where audible frequencies may be affected by noise that is at RF frequencies via effects such as intermodulation or AM demodulation.

"Unintended pathways" may include, among other possibilities, grounds within the receiving device, parasitic capacitances, coupling that may occur into AC power wiring, and the air.

What can be expected regarding such effects, however, is that they will be highly system dependent, and will not have a great deal of predictability.

Regarding the OP’s specific question, though, I would expect that an Ethernet cable that is upstream of his PC would have less chance of making a difference than one that is directly connected to an audio component, where it would presumably be more likely to couple RF noise into sensitive circuit points within the audio system.

Personally I don’t have an Ethernet connection in my audio system, but that’s my take on it.

Regards,
-- Al

@markcooperstein there is one difference - cable look really, really cool.
This thread convinced me to make one really good looking cable, I shall order the best looking TechFlex, cover my Cat6a and - I’ll feel so good.
And I promise I’ll report back here if my sound is better.

Stand by...

@almarg thanks for the great quote of respected expert.
noise and/or RFI is a separate beast shielding, twisting and other means help but moving and turning cable may produce even better affect, removing cable from the system (at least when playing music) solves the ambiguity in the root.

I suggested above to compare playing the same source over the network and directly (by copying file to the media player storage)

@astewart8944 I would prefer an opposite example: someone puts a fancy component into the system and feels good about it, starts hearing better sound or both, good for him/her. Even if doctor says - it should not help...
Hopefully he/she did not spend a lot of money on that and no one who made a component feels like he outsmarted another customer and got easy money.