How Film Sound Design Works
The six layers between a locked picture and a finished soundtrack — and what each one is for.
When a film is picture-locked, the soundtrack is usually production dialogue and a temporary music track. Everything else is built afterwards.
1. Dialogue editing
Production sound is cleaned and made continuous. Room tone fills the gaps. Takes from different days are matched so a scene sounds like one place. This layer is invisible when done well and unmissable when skipped.
2. ADR
Lines the location could not deliver are re-recorded, then edited to sit inside the production sound rather than on top of it. The craft is in the matching, not the recording.
3. Foley
Footsteps, clothing, props, handling — performed to picture in a studio. Foley is what puts physical bodies back into a scene. Without it, characters float.
4. Ambience
Every location gets an acoustic identity. A room's air. A street's distance. The specific quiet of a building at night. This is what tells the audience where they are before anyone says anything.
5. Sound effects
Anything that needs to be designed rather than recorded — impacts, mechanisms, weather, anything that does not exist. Built rather than pulled from a library, when the moment matters.
6. The final mix
All of it balanced together, moment by moment, in the format the film will be shown in. Stereo, 5.1, sometimes Atmos. Stems and an M&E track are produced here too.
Why the order matters
Each layer assumes the one before it is finished. Building Foley against a picture that then changes means rebuilding it. This is why sound post starts at picture lock, and why moving picture lock is expensive in ways that are not obvious from the outside.