I find your post quite interesting and it conflicts with what a North American cable manufacturer has stated on their site. I thought that shielding is beneficial in reducing noise from EMI and RFI..
It is. What I said doesn't conflict, it's a vitally important nuance relating to a very specific use case...
I suspect the North American cable manufacturer was talking about network cables (or even cables) in general and not about the specific use case of switch-to-streamer. Shielding is a hugely powerful tool in cable design because, as I know you know, it's a great way of reducing the amount of RFI reaching downstream circuitry and this applies across an ethernet network and beyond the streamer into digital and of course analog(ue). But the best conductor materials (copper, silver) are the best shield materials, and between a switch and a streamer the last thing you want is a great conductor of noise.
Breaking the noise chain from switch to streamer has far more impact on sound quality than stopping the pickup of local RFI by the cable. So in descending sequence - in this specific use case, though not necessarily elsewhere in a network - I'd rank the cable shielding options as:
1. Best: shielded cable with the shield grounded only at one end; install this grounded end at the switch. Breaks the noise chain from switch to streamer and also directs any RFI noise picked up by the shield away from the streamer.
1a. Next theoretical best (but why bother!): shielded cable with the shield grounded only at one end; install this at the streamer. Breaks the noise chain from switch to streamer
but directs any RFI noise picked up by the shield towards the streamer. Hey, just flip the cable around. See (1).
2. Next real world best: short unshielded cable. Allows ingress of environmental RFI hence importance of keeping it short. Not undermining the good work of the switch in removing huge amounts of RFI noise trumps the little RFI which might be picked up from the local environment. Think Cat 6 UTP.
3. Worst: shielded cable with shield grounded at both ends. Allows the noise stopped by the switch (its whole point) to travel along the shield to the streamer. Think Cat 8 and most "specialist audio" cables.