The Atmosphere A-BT is a remote Bluetooth audio input designed for use with an Atmosphere AZM audio processor, supporting both stereo and mono signals. This expansion allows optimal placement of the Bluetooth receiver for enhanced wireless coverage. The AZM automatically detects the A-BT and applies appropriate audio settings, including makeup gain, EQ, and auto gain control. Stereo source audio is summed to mono before being sent to the AZM.