The light carries a code, not a tiny sound wave
In an optical audio link, the source—such as a television or game console—turns digital audio into a timed pattern of light pulses. A red light-emitting diode flashes inside the connector; the pulses travel down the fiber and reach a sensor at the other end. That sensor converts the changing light back into an electrical signal that the receiving device can decode as audio.
The flashes are not individual sounds, and their speed is not the pitch you hear. They represent digital data: patterns of on and off light that encode the audio information. The receiver reconstructs that information and turns it into the sound sent to speakers or headphones.
Why replacing wire with light matters
A conventional electrical audio cable connects the two devices with a conductor. If their electrical grounds sit at slightly different voltages, unwanted current can flow through that connection and appear as a hum or buzz—a problem called a ground loop. Fiber carries light rather than current, so it breaks that conductive path. The audio data still gets across, but the ground-loop current does not.
The same separation helps keep nearby electrical interference from entering through the audio connection. It does not make the sound inherently more detailed: the result still depends on what audio the devices send and what their electronics can handle. The practical benefit is isolation. A glowing red pulse can deliver the same digital program while leaving the two devices electrically unconnected.
