Few wire types are subjected to as much rhetorical overstatement by manufacturers, reviewers, and high-end audio stores than audio interconnects. It is not unusual for a manufacturer to cite transmission line theory as a basis for a new exotic design. But in reality, transmission line theory is not pertinent to any audio cable less than about a mile in length. Therefore, characteristic impedance of audio cables is not a critical factor. However, capacitance and inductance are critical factors.
Capacitance is the tendency to store electrical charge.
The result can be loss of detail or a dull sound. When evaluating audio line cable, the most critical property to look for is the material used for the dielectric insulation. The lower the storage capacity of the insulator the better. Most audio line cable is a form of coax, using a braid or foil shield. Either is acceptable.