Here’s a simple answer: cables going from analog input devices to DSPs, mixers, etc. need proper shielding and should be as short as possible, with low-resistance connectors. Otherwise, EM radiation can be picked up and interfere with the signal.

Anything traveling digitally? It just needs to arrive at the destination in a timely manner; your cable would have to be really bad to have any influence.

Cables out to analog speakers? As long as you have a decent signal, these can use the crappiest connections and unshielded cables — the worst thing they’ll do is provide interference for OTHER cables they’re near. Just adjust your EQ until the speakers provide the response you’re looking for.