A balanced audio cables require two wires one wire is for the signal and another is for ground. Apart from the balanced cables, unbalanced cables always use ground wire for the returning the signal. Here in case of unbalanced cables, the ground wires use the cable shield.
There have been many things said and written about high-end audio cables. The information is mostly about speaker cables and interlinks and power cords. The effects of speaker cables and interlinks that are created in the high-end equipment. The difference in any cable is very changing and experiments a lot. Always on the lookout for better sounding cables or trying to fine-tune their precious hifi. Most of those people are big spenders