ADR (Automated Dialogue Replacement)

What is ADR in film?

ADR is post-production dialogue work. The actor comes into a recording stage, watches the scene, hears the original production audio as a guide in headphones, and performs the line again until the new take fits the mouth on screen. The dialogue editor then cuts the best take in place of the original.

The older name, looping, comes from the film era: a short section of picture and its guide track were spliced into physical loops that ran over and over while the actor repeated the line. The name survives, alongside additional dialogue recording and the British post-sync. ADR is the same actor re-voicing their own performance in the same language — which is what separates it from dubbing.

It belongs to the dialogue branch of sound in film, alongside effects, Foley and music.

Why do films use ADR?

The recurring reasons:

• Noise. A plane, a generator, rain on a roof, a wind machine or a noisy practical effect can bury a line that no amount of cleanup will save.
• Technical failure. A clipped lav, costume rustle or radio interference.
• Story changes. A line is rewritten in the edit or exposition is added over a character's back — lines with the mouth hidden are the easiest to replace.
• Performance. The picture take is the best one, but a word is swallowed or the reading doesn't land.
• Clean versions. Broadcast and airline cuts often need softer alternates for profanity.
• Crowds. A loop group records the background voices of restaurants, crowds and radio chatter (called walla), so extras on set can stay silent.

Italian productions of the mid-20th century routinely post-synced the whole film. And sometimes the voice itself is replaced: in Greystoke: The Legend of Tarzan (1984), Andie MacDowell's lines were re-voiced by Glenn Close. Singin' in the Rain (1952) builds its entire plot around a studio secretly replacing a star's voice.

How an ADR session works

It starts with the cue sheet. The dialogue or ADR supervisor spots the film with the director and lists every line to replace: timecode in and out, character, the exact words, and the reason (noise, performance, new line). Each entry becomes a cue.

On the stage, the actor watches the cue a few times with the production audio as a guide. Then comes the rhythm everyone who has done ADR knows: three beeps spaced evenly before the line, with the actor speaking where an imaginary fourth beep would fall. Many stages also run a streamer — a vertical line that wipes across the picture and ends on the first word — as a visual countdown. The supervisor and director pick takes for sync and feel.

Habits that make a session productive:

• Keep the line's physical state. If the character was running, climbing or crying, the actor should move, tense up or breathe hard at the mic.
• Record alternates while the actor is warm: a clean version, louder and quieter reads.
• Leave a handle of silence and breath before and after each take so the editor can blend into the production track.

In the edit, alignment tools can nudge a take toward the guide track, but the final judgment is visual: does the voice sit on the lips? That match is the subject of lip sync.

How to make ADR sound like it was recorded on set

Matching ADR to the scene is shared between the recording stage and the sound mix:

• Same mic, same distance. Record with the same type of microphone used on set — often a shotgun for boomed scenes, plus a lav if the production track was a lav — placed at a similar distance and angle.
• Room and space. The stage is dead on purpose; the space is added back with reverb that matches the location. Some mixers go further and worldize — play the dialogue back in a real room or exterior and re-record it there.
• Background bed. Editors lay room tone and ambience under the replaced line so the background doesn't change at the cut.
• Energy and projection. Actors in a quiet booth tend to underplay. A character shouting across a street needs full projection, even if the mic is a meter away.
• Replace the whole exchange when needed. If one side of an exchange is ADR and the reply is production audio, the texture change can be audible; loop both sides.

The cheapest ADR is the one you never need. On set, the location sound team can record wild lines — the actor repeating a problem line off-camera in the same space — which often cut in more naturally than a studio take weeks later.

ADR vs. dubbing: what's the difference?

Both replace dialogue after the shoot and must fit the lips, so the terms get mixed up:

• ADR — the same actor, the same language, usually a handful of lines or scenes. The goal is invisibility: the audience should believe the voice was recorded on set.
• Dubbing — usually different voice actors performing a translated script for a foreign release, covering the entire film.

The tools and stages are often the same, and the craft of voice acting matters in both. When an entire performance is re-voiced by another actor in the same language, as in Greystoke, the industry still tends to call it dubbing or voice replacement rather than ADR. Narration recorded in a booth is a different thing again: voice-over is never meant to match lips at all.

Planning ADR before and after the shoot

ADR is easier when problems are flagged early: the sound mixer's reports note noisy takes, the script supervisor notes line changes, and the editor marks lines to replace as the cut comes together.

FlashBoards helps with the part that is visual. Put frame grabs of every cued shot on one board in scene order, and next to each one note the line, the reason for replacement and the character's state in the scene — out of breath, whispering, across the room. The actor and supervisor arrive knowing what each line must match, with alternate lines on the same board instead of in an email thread.

Further reading

Tomlinson Holman, Sound for Film and Television (Focal Press) · David Lewis Yewdall, Practical Art of Motion Picture Sound (Focal Press)