Just remember that some ethernet cables are designed for audio transmission & not video transmission.
Digital Audio transmission has a slow speed requirement in comparison to fast gigabit requirements that are aimed at bulk data and video transmission. Also, foil shielding adds capacitance that causes audible ringing (jitter) that obscures low level detail. I do not use foil shielding in my audio ethernet cable design.
There are a few other tricks as well...
Cheers,
Pete