I am kind of anal about by cable appearance and routing so I purchased white cat 6 ethernet cable for my Mac Mini since all the other cables were white. I got it from mono-price, nothing exotic, but it did replace cat 5e which I was using. I listen to Pandora frequently and what a difference in sound the cat 6 cable makes. All the music is sharper, cleared, more highs, and better bass. I know cat 6 has a lower S/N ratio and less crosstalk, are these the reasons it sounds so much better?
