ADR is an acronym for “Automatic/Automated Dialogue Replacement” or “Additional Dialogue Recording”. It really depends on whom you ask. It is a process used to replace “bad” dialogue in films and television shows.

How does it work?

An actor/actress (herein referred to as “talent”) stands in front of the microphone watching a scene from the film. Lip synching to the picture, the talent recreates the performance they gave when the film was shot. This process is also commonly referred to as “looping”, a term dating back to the time when the film for a scene was taped in a loop so that it would run in the projector over and over again. The talent could then repeat the line until they performed it correctly. This is also why the process is called “Automatic” Dialogue Replacement as the scene would replay automatically.

Nowadays, the scenes are usually digitized in a computer or recorded onto a videocassette. The talent is then given a cue so they know where to begin speaking their lines.

Common cues include:

  • Beeps: A sequence of three rhythmic beeps preceding the cue is played for the talent. Where the fourth beep should sound, the talent begins their line.
  • Lights: Working much like beeps, a panel of four lights will light up in front of the talent. At regular intervals (usually one second, but this can be set according to the talent’s preference), a light will disappear. When the final light turns off, the talent begins their line.
  • Ribbons: Two vertical lines (commonly called ribbons in the studio) appear, one at each end of the screen. As the scene plays, the ribbons move towards the center of the screen. When the two ribbons meet, the talent begins their line.
  • Time Code: A running clock on the screen telling the talent the current hour, minute, second, and frame of the film. The talent would be told what time their line begins. As the scene plays, the time code rolls and when the time reaches the desired number, the talent begins their line. This system is only used in the direst circumstances. It is extremely difficult to be precise because the line begins on a specific frame and the time code is running anywhere between 24 and 30 frames per second. It becomes very tiring for the talent to concentrate on numbers and performance at the same time. The easier the cue on the senses, the more likely the talent will know when to begin their line.

Recording studios will use any one or a combination of these cues during and ADR session. Most are flexibly equipped in order to make the talent more comfortable. Lights can distract some talent and beeps sometimes drown out the dialogue leading up to the replaced line, making it more difficult for the talent to get into character.

Why must dialogue be replaced?

When shooting a film, the most important thing is the visuals and the performances. It is what you are paying thousands of dollars a day to capture. And if something goes wrong, you must pay thousands more to reshoot the scene. As a result, sound often gets sacrificed. Microphones are very sensitive and pick up a lot of noise. Even on soundproof stages, you can sometimes here the lights buzz or generators outside rumbling. Most scenes shot outdoors are ADR’d. This is usually because of wind but also can be due to heavy traffic or random animals that want to be movie stars.

Big budget action films are predominately ADR’d. These films make the most of explosions, wind machines, and other obscenely loud machinery. These films are also costing so much that crews are sometimes building sets while shooting is going on.

Sometimes directors don’t like the talent’s performance from the set. They will then replace lines with the hopes of improving the scene. Others will sometimes fill in silent spaces with dialogue. This is common in comedies where timing is everything and silence is deadly.

How much dialogue is replaced?

It really depends on the budget of the film and the quality of the production sound. On big budget films, the talent is contractually obligated to be in the studio for a certain number of days. Smaller films will only replace what is absolutely necessary. Studio time is cheaper than reshooting, but not so cheap that it won’t put a dent in your budget.

For an idea of how much some Hollywood films use ADR look no further than Saving Private Ryan. The opening Normandy sequence was shot on a beach (lots of wind and waves), had a few hundred people running around, actors shooting machine guns, and explosions blowing sand everywhere. I would be surprised to find out that any line recorded on set was used in the final film. Rumor has it that 90% of Titanic’s dialogue was ADR (although this is a really high number). This is most likely due to the rushing water and the really big hydraulic lifts that shook the boat during the last half of the film. The dialogue editor for Star Wars Episode II: Attack of the Clones has said that 55% of that film was re-recorded in the studio. And that was a record low for a Star Wars film!

Needless to say, ADR is generally avoided if at all possible. It takes an extremely talented performer to recreate the atmosphere created on set. Studios are sterile places. The talent stands alone at a microphone. They are not on a decorated set, in costume, and speaking with another character. Not to mention the fact that it has been months since the talent last embodied the character they portray. Weighing all of these factors together often results in weaker performances than what was recorded on set. But… if you can’t hear the performance, it’s no good for the film.

Undesireable as it may be, ADR is a necessary and important aspect of the filmmaking process. And when done well… the audience will never know the difference.

For a good demostration of ADR, get your hands on the promotional video for THX Home Theater Systems.