ADR - automated dialogue replacement, known on sets by its older name, looping - is the process of re-recording a film's dialogue in a studio after the shoot, with actors watching their picture and performing their lines again against it. It exists because location audio is a hostage to the shooting day: an airplane, a refrigerator, a rewritten line, or an off-mic actor all leave dialogue that picture needs and sound cannot use. ADR is the fix - and the review round is often where its cue list begins, because the people who notice an unusable line first are usually the ones watching the cut. The review workflow for the audio half of that judgment is in the audio review guide.
Why productions use ADR
The triggers fall into four groups. Noise: locations that defeat boom and lavalier recording - traffic, weather, mechanical hum - leave lines technically present and dramatically unusable. Performance and story changes: rewritten lines, alt takes for tone, and clarity fixes recorded clean in a studio. Technical gaps: off-mic moments, radio-mic dropouts, and lines buried under effects the scene requires. Dubbing preparation: clean dialogue stems recorded for foreign-language versions - the connection point to localization review workflows. Productions budget for ADR as a normal line item rather than a failure state; the craft question is only how much.
The spotting session
ADR begins with a spotting session: the supervising sound team (often with the director) walks the locked or near-locked cut and marks every line that needs replacing - timecode in, timecode out, the line text, the reason. The output is the cue list, the ADR session's score. The modern mechanics of spotting are unglamorous and worth noticing: it is exactly the shape of a frame-accurate comment thread - a timestamped note anchored to a moment, flagging a line, with context - which is why review platforms have quietly become the practical front end of spotting. A reviewer who can pin "this line is unusable, HVAC hum" at 00:42:17 has done the first pass of a sound editor's spotting sheet (frame accuracy is what makes the notes usable).
The 3-beep cue, and why it is called looping
In the booth, the actor syncs to the picture with a cue: "It is common practice to use three beeps as a trigger for cueing the line for the actor" (as sound mixer Leffel describes it in Backstage's ADR explainer) - short beeps ending just before the line lands, so the actor speaks into the gap on rhythm. The name looping is the craft's fossil record: in the film era, the lines to replace were physically looped into a film loop that played over and over while the actor matched it take after take. Digital sessions replaced loops with software streams, but the trade name stuck - the same way picture lock outlived physical picture.
ADR vs dubbing
The two words travel together and mean different jobs: ADR is the original actor re-recording in the original language; dubbing is a replacement performer recording a translation (or replacement voice) over the original performance. The distinction as used here is industry usage rather than a standards-body definition, but it is consistent across the trade literature: ADR preserves the performance and the language; dubbing replaces the language and re-casts the voice. Dubbed releases use the ADR machinery (studios, cues, sync craft) with different inputs - which is why localization pipelines treat "ADR-ready" dialogue as the input spec.
Where ADR meets the review round
The practical loop for productions without a separate spotting pass: reviewers flag unusable dialogue with timestamped comments during the normal review round; the sound team converts those flags into cue entries; the ADR sessions run; the new lines come back as a new audio version - judged on the same review surface, with the audio-specific review checklist and, for broadcast-bound mixes, the loudness targets in broadcast loudness specs. One habit makes the loop trustworthy: audio flags should cite the moment precisely - a timecode anchor, not "somewhere in scene 4" - because every imprecise note becomes an extra spotting pass.
FAQ
Why is it called looping?
The film-era mechanics: lines to be replaced were cut into physical film loops that played repeatedly while the actor matched them take after take. Digital ADR streams the picture instead, but the name stayed - like picture lock, a physical process surviving as vocabulary.
What are the three beeps in an ADR session?
The sync cue: three short beeps preceding the line, ending just before the cue point, giving the actor a rhythmic run-up so the first word lands on the picture. Backstage's ADR explainer quotes a production sound mixer describing exactly this practice as the common cueing method.
ADR vs dubbing - what is the difference?
ADR is the original actor re-recording original-language dialogue in a studio; dubbing is a replacement voice performing a translation over the original performance. Industry usage draws the line by performance and language: ADR preserves both, dubbing replaces them.
Who runs an ADR session?
Typically a supervising sound editor or ADR supervisor running the session, a mix/record engineer capturing the lines, the actor in the booth, and the director when the lines carry creative weight. The cue list from the spotting session is the session's script.
How do I flag lines for ADR from a review round?
Pin a frame-accurate comment at the line's moment with the reason (noise, rewrite, off-mic) and the replacement intent if known. Timecode-anchored notes convert directly into a sound editor's spotting sheet - vague scene-level notes do not, and every imprecise flag costs a pass.