How Do Cordless Headphones Work?

Introduction

The term "cordless headphones" generally refers to headphones that operate using a radio transmitter and set of headphones with built-in radio receiver. The transmitter sends a radio wave version of the audio signal from an audio source to the headphones. Radio waves can travel in all directions and many times will even travel through walls, so radio transmission provides a very flexible option for cordless headphones. The headphones themselves require battery power to operate and are often charged on the transmitter.

Cordless headphones rely upon a radio transmitter to get the audio signal from your stereo system to your headphones. The transmitter is connected to the headphone jack or other audio output on your stereo system or other audio component. The transmitter is then able to receive the audio signal directly from the stereo. In turn, the transmitter converts this signal into radio waves and sends them out into the room.

A set of cordless headphones contains a built-in receiver designed to receive the radio waves. Once the radio waves have been received, the audio signal is converted back into its electrical form and sent into the dynamic driver in each ear.

A dynamic driver operates just like a stereo speaker: alternating current flows through an electromagnetic coil and when the current alters direction the electromagnet's North/South polarities alternate. As the polarities alternate, the coil vibrates back and forth because of a stationary magnet that is built into the driver. The coil is constantly repelled or attracted to the magnet depending upon its polarity at the given time. When the coil moves, a diaphragm moves along with the coil and pushes air molecules that carry sound waves into your ears. Because the motion of the voice coil is based upon the frequencies contained within the original audio, the sound waves are a direct replication of the audio.