Dialog Replacement in Films and Television
By Dane Davis
One of the primary goals of film is to create the illusion of consistent time and space onscreen. As with the visual aspects of the film, the sound — including dialog — must support this illusion. When a production recording of dialog is unusable due to intelligibility or noise problems, it is replaced by a clean recording that precisely fits the existing picture. The process of recording this replacement dialog is called Automated (or Automatic) Dialog Replacement (ADR), or looping.
In ADR, the original actor or actress recreates his or her character’s vocal performance, one line at a time, in a sonically controlled environment. This technique, though often necessary, makes it considerably more complex for sound editors to maintain the overall illusion of consistency.
Making It Clear
ADR is most commonly used when noise in the production environment makes it impossible to understand the dialog that was initially recorded. Despite the best efforts of the production mixer on location, sometimes the level and timbre of other sounds mask the actor’s voice, making the dialog unintelligible. A key function of the ADR supervisor is assessing this threshold of intelligibility, and then persuading an often-reluctant director and picture editor that ADR is needed in a particular scene.
Matching Voices to Action
Sometimes a director believes that an actor isn’t capable of delivering the vocal performance needed for a character. When the actor you see onscreen has had his or her voice replaced by a different actor, it’s called “revoicing.” A casting call is sent out to actors with strong loop-stage experience. When the revoicing actor has been cast, the ADR proceeds normally. Fortunately for everyone, this is rare. It is more common for “voice-alike” actors to be brought in to record temp lines for audience previews, to save the lead (busy and expensive) actors from having to perform lines of dialog in ADR that may not make it into the final cut.
Breaths are also often the victims of actors jumping right in on each other, even if the words themselves are intact and separate. Again, if the dialog editor doesn’t have the material to reconstruct the natural breathing patterns of the people in close-up, each actor (or a vocal impostor) must recreate that rhythm on the stage. In scenes where the characters are exhibiting exertion, their huffs, puffs, gasps, and other respiratory actions — called “efforts” — often need to be recorded cleanly to project their dramatic power to the audience.
When the lead actor does not have the time or inclination to provide utterances like breaths, a vocal stand-in may be brought in. These specialized “heard-but-not-seen” performers are generally part of a “loop group.”
The group leader (who usually acts with the group onstage) finds actors that can speak, if not actually converse, in a particular language and a particular regional accent. The actors then write or improvise suitable dialog within the setting of each scene. A single movie may include such settings as a Parisian café full of academics, a factory in Sao Paulo, a corporate board meeting in Manhattan, a party in Beirut, a Jamaican political meeting, and a beach in Malibu. Once the ADR supervisor has determined the film’s needs, the walla group leader assembles the smallest possible group (usually between eight and sixteen actors) that can still provide all the linguistic and socioeconomic flavors for the recording session. Requirements for later international distribution also must be considered when mixing various languages and accents together.
In the beginning of the post sound process, the ADR supervisor looks at the entire movie with the director and picture editor in what is called an “ADR spotting session.” Usually the editor already has a list of new lines and replacement lines that have been discussed during the editing process. During the spotting session, all these cues are discussed, and the ADR Supervisor usually has lots of suggestions for loop lines after listening to the editor’s track for anything unclear. Other vocal elements for TV sets, radios, phone conversations, etc. are also added to the cue list, even if they are “to be written” (TBW) later. These TBW lines are placeholders for the casting and scheduling of actors. At the end of the spotting session, the supervisor takes all this information and compiles a master ADR cue list, with exact start and stop frames for each line, which is printed out for approval and reference by the director, editor, and producers.
In a looping session, the actor and the ADR mixer get printouts of the lines that the actor must record. About ten lines per hour are usually accomplished on the ADR stage, depending on how many takes the actor and director require. Some actors have a natural gift for this awkward process, while others find it excruciatingly difficult.
Pro Tools Saves the ADR
Technically, the ADR process has become somewhat simpler than it used to be, thanks to applications such as Pro Tools. Not that long ago, a physical loop of film had to be cut for each line to be replaced. These have now been replaced by virtual loops played on a computer screen. As with the original method, the actor watches the picture and synchronizes his or her voice to the action as the mixer records it.
As each take is recorded, the ADR supervisor notes the performance, the sync accuracy, and the actor or director’s preferences. Some supervisors will record a few sync takes, then let the actor keep performing the line “wild” until he or she achieves the original on-set character nuance. This method can be a lot more time-consuming for the ADR editor, but with “sub-frame” editing in Pro Tools, miraculous synchronization can be achieved. Takes that feel perfect in emotional tone and inflection, but look “rubbery” unedited against the picture, can be reshaped to perfection with editing tools like the Synchro Arts VocALign plug-in.
Some vocal actions, like the mouth shapes for the sounds “p,” ”b,” “v,” and “m,” require very exact synchronization or they look completely wrong, even to a layman’s eye. Other consonant and vowel sounds allow a bit more flexibility — it’s often possible to “cheat” a different rhythm, or even different words, onto the actor’s lips and mouth. Sometimes a line looks more natural with a looser synchronization than with an over-edited tight fit. Maintaining the balance between natural performance and lip-sync is the primary challenge of the ADR editor. With experience, the editor masters this threshold of believability.
Keeping It Subliminal
Besides keeping the ADR session running as efficiently as possible, the ADR mixer’s job is to match the acoustic quality of the production recording as much as possible, to make it easier for the re-recording mixer to merge production dialog and ADR. The mixer needs to keep many variables in mind, including what type of microphone was originally used, the room acoustics, the axis angle of the mic, and the distance from the mic to the actor’s mouth. If the original production mixer used a lavalier, a shotgun, or a less directional mic on a boom, then the ADR loop must be recorded with a similar mic.
Once all the necessary ADR gets recorded and edited, the dialog re-recording mixer matches each loop line to its surrounding production, paying special attention to sound level, equalization, and room acoustics. This is where the illusion of continuous time and space is ultimately achieved — or not. When it is achieved, all the dialog in a film — whether originating in production or ADR — will be accepted without question as happening in a continuous sequence, right where the camera is pointing. A lot of work goes into that aural magic act.