The Sonifex CM-CU1 Commentator Unit and Line Input offers the same high quality, robust specification as the CM-CU21, with a feature set tailored to single commentator applications. It provides a fully featured commentator position and a line-level input. The unit has an individual commentator output, with an additional output providing a mix of commentator and line input audio. A limit indicator on the main panel shows when the adjustable limiter on the main output is active, and a bright 21 segment LED PPM meter, which can be disabled, shows the main output level.

The line input can be configured to remain present at the mix output even if the commentator is off air, making it useful for routing crowd effects or pre-recorded material to the programme feed. Its presence in the commentator's headphones is also configurable to suit the application. Four talkback output channels, with a built in limiter, are available to the commentator and they can be linked to provide simultaneous operation. Activation of one or more talkback channels removes the commentator audio from the main output until all talkback channels are deactivated.

A wide input gain range and switchable phantom power allows support of a variety of microphone types including low output ribbon mics, headsets and high output phantom powered microphones. There are 5 transformer balanced return audio inputs which, along with the commentator input, are routed to the headphone monitor controls. With these headphone controls, any monitor input can be adjusted and sent to either the left, right or both ears. A GPIO port gives an open-collector driven output indication of any active On-Air or talkback channel and four remote inputs provide an e