Ethernet Cables, do they make a difference?

Ethernet cable is digital.
As such it cannot change the quality of the music.
There are very few bytes to deliver over the cable. Network protocols like TCP/IP or whichever one you use take care of the data continuity so the song file on the remote storage is identical to the file delivered to the media player and DAC. The sequence of the bytes is the same - guaranteed. It will be delivered ahead of the time when it will be played by media player and processed by the DAC since the speed and throughput of the cheapest cable exceeds the needs of the delivery channel. Media player will take care of the buffering of the data when data packets coming out of the  Ethernet cable into the network card and put back together into the continuous stream of bytes.

Quality of the music depends on the components in the chain starting from DAC all the way to the speakers and the room, furniture in it and so on - the analog components so to say.

However Ethernet cable may impact the quality of the sound, introduce noises of all kinds.
That highly depends on the design of each individual system.
"highly flawed system" may be one which is not shielded properly and not shielded Ethernet cable will create all kind of parasite noises.
What may look and sound like " highly resolving system" may be easily brought out of balance by poorly manufactured  Ethernet cable. Most likely it will not but there is a chance. Reports of improvements with high quality cables just prove that.

The case when placebo affect takes place has all rights for existence: What looks good and has a significant price tag must sound good.

This debate will never end due to the high permutation of the components and configurations in your systems. Too many variables in this equation.
But go out there, try, experiment and improve, If you like the sound - keep the cable, if not - take it back and as for a refund :-)

@burgh heavy shielding in industrial environment has many reasons (as you well aware of), standards, codes, safety... you name it.
Besides  Profinet, CanBus or any serial bus protocols are considered real time and delivery of each individual message in time is critical so they are mostly shielded from outside world.

In Audio world at home we are free to do whatever we like, especially in lo voltage circuits - so experimental lab is open for suggestions.

Benzman, it's real simple. It's vastly more likely that those who think they hear differences in Ethernet cables are experiencing a mental phenomenon than there's some difference in the cable. If you buy into this snake oil, then do you also think memory chips have their own sound? Do routers and switches have their own sound? According to you they should! There's no evidence to support your claims. 

Benzman 4-25-2018
I don’t understand why folks that choose not to believe in differences in cabling actually debate with those of us that can detect differences in sound quality.

That seems to be a perennial question in debates such as this. And often parties on both sides of such debates tend to impute a variety of nefarious motivations to those on the other side.

My own belief on this question, which I haven’t previously stated, is as follows: I believe that the great majority of those on both sides of such debates are sincere in their beliefs and in their statements. What I believe is usually the motivation of the so-called naysayers can be illustrated with a hypothetical situation: Let’s say that in a music forum various classical music buffs were discussing the music of Johann Sebastian Bach. And let’s say that someone submitted a post asserting in no uncertain terms that Bach was a third rate hack as a composer. Certainly the other participants would feel a natural urge to set the record straight. And it is my belief that so-called naysayers believe, rightly or wrongly (and perhaps in many situations the truth is sufficiently nuanced to lie somewhere in between), that what is being asserted by those on the other side of debates such as this is comparably ridiculous, as well as impossible. And consequently I believe their motivation in such situations is likely to be similar to that of the Bach connoisseurs in the hypothetical situation I described.

Regards,
-- Al

acepilot71
Ethernet cable is digital.
As such it cannot change the quality of the music.

>>>>Sorry, that’s the same illogical argument naysayers have been using for years to try to explain why there can be no differences between digital cables, the ones that connect to the external DAC - because it’s digital. The problem with that illogical argument is all signals - analog OR digital - are electromagnetic waves. As such they are subject to the same cable characteristics as any other cable - geometry, conductor material/purity, dielectric material, directionality, etc.