7 min read
What a production sound mixer actually does on set
The sound department is judged on what post receives. Here is the job, the kit, and the handover that decides whether the shoot was a success.
The production sound mixer is responsible for everything the audience will hear that was recorded on the day: dialogue, perspective, usable atmosphere and the metadata that lets post find it all again.
The bag
- A multitrack recorder, typically 8 to 16 tracks with timecode.
- A boom microphone, usually a shotgun outdoors and a hypercardioid inside.
- Radio microphones for each principal, plus spares and rigging supplies.
- Timecode boxes for camera sync, headphones, and a comms system for the director and script.
Who does what
The mixer sets levels, decides which microphone carries each line and writes the sound report. The boom operator places the microphone and follows the action. On bigger crews a utility handles radios, rigging and cable runs.
Tracks, not a mix
Modern practice is to record every microphone as its own isolated track and send a convenience mix to camera or to the director's headphones. Post edits from the isolated tracks, so the mix is a monitoring tool rather than a deliverable.
That is why the day ends with poly WAVs: one file per take containing boom, each lav and the mix, with the track names and timecode written into the file.
What good sound looks like on the day
- Headroom, with peaks around minus 12 to minus 18 dBFS and nothing clipping.
- Perspective that matches the shot, close for close ups, wider for wides.
- Room tone captured at every location, and wild lines for anything unusable.
- Consistent naming, scene and take, correct on every file.
The handover
At wrap, post receives the cards, the sound report and the metadata. If the editorial team asks for mono stems, that split should be done without changing sample rate, bit depth or channel order, and with the recorder's track names carried into the file names.
A clean handover is what makes a mixer rehireable. It is also entirely a file management question, and it can be done in minutes with a browser based splitter that never uploads the rushes.