The Complete Handbook of Audio Transmitters

Chapter 1: Understanding Audio Transmitters

An audio transmitter is any device that converts an audio signal into a radio frequency (RF) carrier wave for wireless transmission to a compatible receiver. The purpose is simple: to physically decouple the sound source from the sound reproduction or amplification system, enabling movement, safety, or aesthetics that a cable would otherwise preclude. You see these systems in action on a Broadway stage where an actor moves freely across the set, in a large conference room where each presenter needs a microphone without trailing a wire, or in a church where the pastor paces the dais. The transmitter is the "microphone side" of the wireless chain, but the same principles apply to in-ear monitor systems that send audio to a performer's earpiece.

To understand what a transmitter does, you have to look at the signal path as a whole. The chain begins with a transducer, like a microphone element, which converts acoustic energy into a tiny electrical voltage. That voltage is an analog representation of the sound wave, but it is far too weak and spectrally complex to travel through the air effectively. The transmitter's job is to prepare that signal for a journey through space and then to send it on its way. It does this through a process of modulation, where the audio signal is applied to a much higher frequency carrier wave. This carrier wave is the "vehicle" that travels through the air at the speed of light, eventually being received by