A Motion Picture Production Sound Mixer is responsible for recording film/video production dialogue and fx. He usually commands a crew consisting of one or more boom persons, but if need be can also run a solo setup.

The sound mixer is considered a department head, and is thus completely responsible for all aspects of production sound including the hiring of boom operators, planning the technical setup involving sound including both sound equipment and ancillary devices involved in syncing and time offsets, anticipating and discussing sound-related problems with the rest of the crew, and ordering and preparing the sound equipment to be used on the set.