Treating the cable as a two-port network is oversimplifying the system by ignoring that audio cables often (undesirably) act as antennas.
Directional cables have the shield disconnected at one end to ensure there is no LF current path through the shield, thus minimizing mains hum picked up by high-impedance instruments.
Of course, balanced cables (where the shield is exactly a shield, and not also a signal path) do not have this problem.
Directional cables have the shield disconnected at one end to ensure there is no LF current path through the shield, thus minimizing mains hum picked up by high-impedance instruments.
Of course, balanced cables (where the shield is exactly a shield, and not also a signal path) do not have this problem.
The Rane Note on sound interconnection has more info: https://www.ranecommercial.com/legacy/note110.html