Automated or automatic dialogue replacement (ADR) is a process whereby dialogue is re-recorded in a studio during post-production to match picture filmed during principal photography. As the name implies, this better quality re-recording of an actor’s dialogue replaces the previously recorded poor quality audio. ADR is necessary when, for one reason or another, no suitable dialogue was recorded during principal photography. Some of these reasons are:
- The location was too noisy
- An external sound ruined the audio in a “good” take (like a construction nearby).
- A microphone could not be used (maybe it was malfunctioning).
- The director wanted to shout directions during filming (so no usable audio could be recorded)
ADR is sometimes incorrectly called Additional Dialogue Recording. This is inaccurate because it implies either filming extra scenes (after principal photography has concluded) or recording dialogue that was written at a later date. Not so. To reiterate: ADR takes place during post-production when the production sound was not recorded properly. No cameras are used, and the actors are not in costume, otherwise this would be known as a pick-up.
Example of ADR
Check out this great clip I found on YouTube to see how the pros do it. The video should automatically start at 5:48 because that’s where the “action” happens. If you want more information, watch the clip from the beginning.
When is ADR a Good Idea?
Automatic Dialogue Replacement is not cheap. ADR is an expensive process because renting a post-production facility, in addition to hiring sound engineers and sound mixers, is costly. In student films, your actors may be free, but if you are ADRing a feature film or TV show, the talent can be ridiculously expensive. Not to mention that, getting the voices to match previously recorded footage is time-consuming. Actors often need several attempts, which is why the process is also known as “looping.” Back in the day, the film would play in a loop so that actors could have more than one try to get it right. Nowadays, you can mimic that effect with your digital editing software. It bears emphasizing that in addition to the time needed to get the voices to match, even more time is necessary to mix the audio and add all those layers of effects.
If ADR is expensive and time-consuming, then when should you do it? ADR should never be your first choice. If you can get good clean dialogue on set inexpensively and efficiently, then do it. Consider doing ADR when, for one reason or another, recording clean dialogue on set would be more time-consuming and expensive than just replacing the dialogue in post. For instance, if you are shooting on location, and some unexpected police activity brings loud sirens and other disturbances to your set (it happens!), waiting out would be a waste of time. It’s probably better to just bite the bullet, get your footage, and replace the dialogue later. (Pro Tip: You always want to record audio because the “guide track” will assist the actors doing audio ADR* in post.)
*Audio ADR: Actors deliver their performance matching audio from the original take. The opposite would be Visual ADR, whereby actors deliver their performance matching the mouth movement from the original take.