Yep, spot on. 'Crisp clarity' is probably an RF artifact as opposed to being part of the music. The trouble is that the devices that the cables are plugged into also act as aerials so good cable shielding is no guarantee of keeping RF out. And whilst the shield might protect the central conductor it is possible that depending on earthing arrangements, the shield itself might pick up RF and carry it to the device in the ground plane. RF noise is sneaky stuff and can jump past/over some isolation measures.