How do film sound and Foley work?

Most of what you hear in a film was never recorded on set. Hang a boom mic just out of shot, snap celery for breaking bones, build a monster's roar from three layers, re-voice a line in sync, and fly a helicopter over your head in Dolby Atmos.

Read how it works: How do film sound and Foley work? · The history of film sound · More boxes on Glassbox

Chapters in this interactive model

1. Recording the voices on set: Aim a boom mic, clip on a lavalier, and see why the mic hangs just out of frame.
2. Foley: sounds made by hand: Walk in the pits, snap celery for bones, and try to perform footsteps in sync.
3. Designing big sounds: Build a monster’s roar from three layers, bend its pitch, and fly a spaceship past your ears.
4. Re-recording the dialogue: ADR: Loop a scene, count the beeps, and find out how far lips and words can drift apart.
5. The final mix: stems, loudness and Atmos: Ride five faders, duck the music under the words, and fly a helicopter around the room.
6. Hearing it in the cinema: Follow the sound from the digital package to your seat, and see why the screen is full of holes.