STUDIO25 Audio Post
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Chapter 02Production Sound Basics

Every file you conform, edit and mix was recorded on set by the production sound team. Knowing how they work tells you what to expect, what to look for, and what to ask.

0 of 7 lessons done

You will learn toAbout 3 hours + exercise

  • Name the sound crew and what each person delivers
  • Tell boom, lapel and mix tracks apart
  • Read scene, shot and take, and call a slate
  • Explain timecode, jamming and frame rates
  • Read a file's metadata and a sound report

Lesson 2.115 min

Production sound and the crew

In short

Production sound is everything recorded on set. Its main job is clean dialogue, plus the room tone and wild lines you'll need later.

WhoWhat they do
Production sound mixerRuns the recorder, mixes the microphones live, watches levels and noise, names the files and writes the sound report.
Boom operatorHolds the boom microphone just out of frame, following each actor line by line.
Sound utility (2nd assistant)Fits the lapel mics with the costume team, looks after radio mics, batteries, cables and timecode boxes.

At the end of each day the mixer delivers the sound rolls (the recorded files) and the sound report. Picture editorial uses them to sync dailies. Weeks later, they're exactly what you conform from.

Besides the takes, a good mixer records:

  • Room tone: 30–60 seconds of the room with everyone silent. You'll use it to fill gaps between lines.
  • Wild lines: an actor repeating a line without the camera, when the take had noise over it.
  • Wild tracks: sounds of the location or props, recorded without picture.
What Sound Mixers REALLY Do On SetA short overview of the job.Deity Microphones3:28How to Be a Sound Mixer | On-Set Audio MasterclassA mixer walks through a real set: gear, booming, radio mics.Deity Microphones14:39
Next · Microphones and tracks →

Lesson 2.220 min

Microphones and tracks

In short

Each microphone is recorded on its own track, called an iso. The mixer also records a mix of them all. Post works from the isos.

MicrophoneSounds likeWatch out for
BoomNatural, with the room around the voice. Usually the first choice.Distance on wide shots, room echo, the operator missing a line.
Lapel (lavalier) on a radio transmitterClose and clean, even in noise.Clothing rustle, a boxy chest sound, radio dropouts.
Plant micA mic hidden in the set, such as in a car or behind a lamp.It only works when the actor is near it.

A typical take is one file with several tracks. For our practice scene:

TrackNameWhat it is
1–2MIX L · MIX RThe mixer's live mix. Picture editors often cut with this.
3BOOMThe boom iso.
4LAV MAYAMaya's lapel iso.
5LAV DEVDev's lapel iso.
6PLANTA plant mic on the kitchen counter.
Track order is not standard

Every mixer sets up their own layout, and it can change during a shoot. Never assume track 3 is the boom. Read the track names in the file's metadata (lesson 2.6) or on the sound report.

How to Use Boom and Lavalier MicrophonesWhen to use each, and how they're placed.B&H Photo Video12:56
Next · Scene, shot and take →

Lesson 2.320 min

Scene, shot and take

In short

The scene comes from the script. A shot is one camera setup. A take is one attempt at that shot. Every recording is labelled with all three.

Scene numbers come from the script. Each time the camera moves or changes lens, that's a new shot (or setup). Each time the camera rolls on that shot, that's a new take, counting from 1. Productions write this in one of three ways. Always ask which one your production uses.

SystemHow it's writtenExample
Scene · shot · takeScene number, shot number, take number.Scene 22 · Shot 3 · Take 2
Scene + letter (US)The first setup is just the scene number. Each new setup adds a letter: 22, 22A, 22B…22B · Take 2
Slate number (European)A running number for the whole shoot, going up with every setup. Scenes are tracked separately.Slate 145 · Take 2

Special labels you'll see

PU · Pickup
The take starts partway through the scene.
AFS · After false start
The take was clapped but stopped before action. Same take number, marked AFS.
Series
Several attempts in one long take without cutting.
MOS
Picture with no sound recorded.
WT · Wild track / wild lines
Sound recorded without picture.
RT · Room tone
The sound of the room with everyone silent.
Circled take
A take the director liked. Marked on the report and in the file.
Next · Slating →

Lesson 2.420 min

Slating

In short

The slate is read aloud for sound, shown to camera for picture, then clapped. The clap is one sharp moment that lines the two up.

  1. "Roll sound"

    The mixer starts recording and answers "Speed" when the recorder is running.

  2. "Roll camera"

    The camera rolls. The operator says "Mark it".

  3. The call

    The 2nd AC holds the slate in frame and reads it clearly, for example "Scene 22 Apple, take 3".

  4. The clap

    The sticks close sharply, then the slate leaves frame. If the clap was missed, they call "Second sticks" and clap again.

Call the slate

Try each system
Said aloud

Letters are said as words

So "B" and "D" can't be confused: Apple, Baker, Charlie, Delta, Echo, Foxtrot… The letters I and O are skipped because they look like 1 and 0. Exact words vary from set to set.

How To Use A Clapperboard The RIGHT WayCalls, tail slates, MOS and second sticks, from a working camera assistant.In Depth Cine16:01The Clapperboard — How to Use a Film Slate (And Why You Should)What goes on the board, and why.StudioBinder10:50
Next · Timecode and frame rates →

Lesson 2.525 min

Timecode and frame rates

In short

Timecode is a clock in every camera and recorder. Jamming sets them all to the same time, so sound and picture can be matched automatically.

Timecode reads hours:minutes:seconds:frames, for example 14:21:58:00. On most shoots it runs as time of day (also called free run): it keeps counting whether or not anyone is recording.

Jamming copies one master clock into every device. After that, each device keeps time on its own clock, and clocks slowly drift. So the crew re-jams at the start of the day, after lunch, and after battery changes.

A master timecode source is jammed into the camera, the sound recorder and a timecode slate. Afterwards each runs on its own clock.MASTER CLOCK14:21:58:00JAMCameraSound recorderTimecode slateruns on its own clockruns on its own clockruns on its own clock

Frame rates

The recorder's timecode must use the same frame rate as the camera. A mismatch is the classic cause of sync that slowly drifts in post.

RateWhere you'll meet it
23.976Most digital film and series work. Cameras often label it "24", so check the real number.
24True 24 frames per second: film cameras and digital cinema.
25TV in PAL countries, including India and Europe.
29.97TV in NTSC countries such as the US and Japan. The only common rate that can use drop-frame timecode.
Drop frame, in one line

At 29.97, drop-frame timecode skips some frame numbers (never actual frames) so the clock stays in step with real time. It's written with semicolons: 01;00;00;00. Film work almost always uses non-drop.

Recording format

Production sound is recorded at 48 kHz, in 24-bit or 32-bit float WAV files. 32-bit float makes clipping almost impossible, but check that post can take it.

Tentacle Sync – Timecode Workflow SolutionHow a timecode box jams and syncs cameras and recorders.Official · Tentacle Sync3:42How to Jam Sync Timecode Generators (Tentacle/Deity/Sound Devices)Jamming step by step across brands.Creative Video Tips10:06
Next · Files, folders and metadata →

Lesson 2.630 min

Files, folders and metadata

In short

Each take is a WAV file. Inside it, hidden metadata records the roll, scene, take, timecode and track names. Conform tools read this, not the file name.

A sound roll is one batch of recordings, usually one shooting day or one card, with a name like SR014. One folder per day is the industry norm. Takes are saved either as one poly file with all tracks inside, or as one mono file per track.

A typical delivery
KITCHEN/The production
  SR014_260514/One folder per sound roll / shooting day
    22A_T01.WAV … 22A_T04.WAVTakes, named scene + take
    22_WT01.WAV · 22_RT01.WAVWild lines and room tone
    SR014_SoundReport.pdfThe sound report
File names are not reliable

Naming depends on the recorder and the mixer: 22A_T03.WAV, SR014-22A-003.WAV and T003.WAV can all be the same take. File numbers also restart on every roll. Trust the metadata.

Inspect a file

22A_T03.WAV · click any line
Metadata

Click a line

This is what a conform tool reads from one take of our practice scene. Start with TAPE.

The sound report

The mixer's log of the day: a header (production, date, roll, recorder, sample rate, frame rate, track layout) and one line per take with notes. Circled takes are the director's favourites. Read the notes: they tell you about planes, rustle and wild lines before you hear them.

FileSceneTakeStart TCNotes
22A_T01.WAV22A114:18:02:10False start
22A_T02.WAV22A214:20:51:00Dev off mic at end
◯ 22A_T03.WAV22A314:21:58:00Plane at end, after cut
◯ 22A_T04.WAV22A414:22:40:00Good. Lav Maya rustle 00:12
22_WT01.WAV22WT114:31:40:00Wild lines: Maya "Not tonight" ×3
22_RT01.WAV22RT114:33:05:00Room tone, 60 s, kitchen, fridge off

Sample report · Roll SR014 · 48 kHz / 24-bit · 23.976 ND · ◯ = circled take

Sound Devices & Video Devices Recorder Metadata and Sound ReportsHow a recorder writes metadata and makes the sound report.Official · Sound Devices6:03Timecode, Jamming & Metadata on the Sound Devices 664, Slate, Camera.Timecode and metadata from recorder to slate to camera, for film students.Beni Harper20:51
Next · Practise and check →

Lesson 2.71–2 h

Practise and check

Exercise: read a real delivery

Use location sound from any film you have access to, or record your own: one short scene, two takes, plus room tone.

  1. Map the folders

    Write down the roll names, how files are named, and whether takes are poly or mono.

  2. Read the metadata

    Open one take in Pro Tools' Workspace browser or a metadata app. Note the scene, take, roll, timecode, frame rate and track names.

  3. Compare with the sound report

    Check the circled takes and notes match the files. List anything missing or different.

  4. Find the extras

    Locate the room tone and any wild lines, and note which scene each belongs to.

Quick check

0 / 6

1. Which tracks does a dialogue editor mainly work from?

2. How do you know which track is the boom?

3. The camera moves to a close-up. What changes?

4. Why re-jam timecode during the day?

5. The camera says "24p". What should you check?

6. In iXML metadata, which field holds the sound roll name?

Key terms

Production sound
Everything recorded on set.
Boom
A directional mic on a pole, just out of frame.
Lapel / lavalier
A small mic hidden on the actor, usually on a radio transmitter.
Iso
One microphone on its own track.
Mix track
The mixer's live blend of the microphones.
Sound roll
One batch of recordings, usually a day or a card.
Slate
The clapperboard, and the act of calling and clapping it.
Tail slate
A slate at the end of a take, held upside down.
Timecode
A clock stamped on every recording: hh:mm:ss:ff.
Jam
Setting every device's clock to one master.
Frame rate
Frames per second: 23.976, 24, 25, 29.97.
Poly / mono WAV
All tracks in one file, or one file per track.
BWF / iXML
The two metadata blocks inside a location WAV.
Sound report
The mixer's log of every take and its notes.
Room tone
The sound of the room with everyone silent.
Wild line
A line re-recorded without the camera.
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