In a wireless microphone system, the device that transmits the audio signal output from the microphone through the air as a radio frequency. In a lapel system it's sometimes referred to as a 'body-pack'. This is where the microphone plugs into, where a battery is stored, and where the electronics are that change the audio signal so it can be sent out an antenna and into the air to be picked up by a receiver at another location.

Source: [ Church Audio & Acoustics Glossary]

[[Category: Acoustics]]