1. A production sound mixer, location sound recordist, location sound engineer or simply sound mixer is the member of a film crew or television crew responsible for recording all sound recording on set during the filmmaking or television production using professional audio equipment, for later inclusion in the finished product, or for reference to be used by the sound designer, sound effects editors, or foley artists. This requires choice and deployment of microphones, choice of recording media, and mixing of audio signals in real time.
Usually, the recordist will arrive on location with his/her own equipment, which normally includes microphones, radio systems, booms, mixing desk, audio storage, headphones, cables, tools, and a small amount of stationery for making notes and logs. The recordist may be asked to capture a wide variety of sound on location, and must also consider the format of the finished product (mono, stereo or surround sound). The recorded production sound track is later combined with other elements or re-recorded by automatic dialogue replacement.
Often when filming on video, the sound recordist may record audio directly onto the camera rather than use a separate medium, although a separate copy is often made, as it both provides an extra copy which may have more tracks and also may include other sound captured without the camera.
The sound mixer is considered a department head, and is thus completely responsible for all aspects of production sound including the hiring of a boom operator and utility sound technician, 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.