The Complete Handbook of Audio & Video Cables

Chapter 1: Understanding Audio & Video Cables

An audio or video cable is a physical conductor or bundle of conductors designed to carry an electrical signal from one device to another without degrading that signal in transit. That simple statement masks substantial complexity. Thousands of different cable specifications exist because signal integrity—the quality and fidelity of the signal when it arrives—depends on the cable's material, geometry, shielding, impedance, capacitance, and the environment through which it travels. A cable that works perfectly in one context may fail or introduce noise in another, not because it is defective, but because it was specified for the wrong application.

To understand why, consider what actually happens inside a cable. When an audio signal travels down a wire, it does not flow like water through a pipe. The signal is an alternating electrical voltage that oscillates back and forth many times per second. An analog audio signal might oscillate between roughly 20 and 20,000 times per second. A digital video signal oscillates far faster—a standard HDMI signal, for example, transitions between voltage states billions of times per second. As these electrical oscillations travel down the conductor, they interact with the material around them. The insulation surrounding the conductor has electrical properties. The other conductors nearby—whether another wire in the same bundle or an external source of electrical noise in the room—create an electromagnetic field that influences the signal. The length of the cable introduces delay. Reflections can occur at the point where the signal meets