Just expanding on the issue of common mode noise. This is a major source of "pollution" in this time of connected devices, e.g. smart phones and tablets, connected appliances e.g. doorbell, kitchen and household appliances.
Folks think that copper Ethernet cables can't impact sound quality because of the specifications for (copper) Ethernet: that everything is "bit perfect" and if a packet is dropped in transmission it gets re-sent, so what's the problem? Well, there's a whole host of problems. Copper Ethernet is actually pretty "dirty" with respect to susceptibility to noise factors. For IT applications, this is not a problem, as the output is "discrete"; either the pixel gets printed in a print-out, or displayed on a computer monitor or it doesn't. And with Ethernet "error correction", it almost always does....so, no worries.
But streaming musical content is NOT discrete; its "continuous data", and...the timing is, in the words of Hans Beekhuzen, "hyper-critical" (this is why folks use those ultra-trick clocks for DACs, etc., for example). Also, Ethernet cables, like many copper cable specifications, are susceptible to the usual noise factors, e.g. lack of galvanic isolation, EMI/RFI, etc. They are also susceptible to low-impedance and high-impedance AC leakage currents, which are usually caused by crap switch-mode power supplies and can be made worse by...shielded Ethernet cables where the shield is connected to the RJ45 connectors at both ends. These noise factors contribute to digital audio quality, adding "digital glare", jitter and...clock phase noise.
And then there's the common mode noise, as well.
The Shunyata Alpha and Sigma Ethernet cables are the only ones I am aware of that have an effective common mode noise (CN) filter, and the function of this filter is very clearly discernable. The Alpha brings a notably lower noise floor and cleaner, more "open", spacious and airy and extended over the excellent attributes of Venom. And Sigma, with two CN filters, builds further upon that; the addition of the 2nd CN filter brings increased presentation of subtle details, textures, articulation, and breath and phrasing in vocals and an even lower noise floor. I'm literally hearing content on well-known songs that I simply have not heard before.
All this adds up to a musical presentation is much more "analog", open, airy, spacious, dimensional in character.
But, one has to open to trying these cables to understand...
