Hack 51. Mobile Audio Booth

You've probably got a perfectly good sound booth at your house, and you don't even know it.

Recording clear dialogue can often be a significant challenge. Outdoor shoots battle unwanted noise from wind [Hack #52], aircraft, traffic, and more, while indoor shots often have to contend with interference from room echoes, central air systems, computer fans, and electrical hum [Hack #56]. When these factors are combined with a limited audio toolset, capturing clear, understandable on-set dialogue that will hold up over a background music score becomes a nearly impossible task.

Even the most expensive professional productions have to contend with some of these challenges. Often the solution is to hold an Additional Dialogue Recording (ADR) session in a recording studio after a shoot, where the actor or actress records their lines in a noise-free, echo-free sound booth. Another advantage to ADR is that the performer can focus solely on their delivery of the dialogue, while having the script in front of them, free from concerns about body position, hitting marks, and other on-set distractions. The dialogue recorded in the studio is then used to replace the on-set audio, resulting in crystal clear sound in the finished movie.

5.2.1. Finding a Sound Booth

On a limited budget, however, renting a sound studio for an ADR session could easily be out of reach. There is however a readily accessible no-budget alternative: record your ADR inside a parked car.

Most modern car interiors are specifically designed to be quiet, deadening much of the sound from outside and limiting echoes within the cabin itself. More expensive luxury cars tend to have the best audio characteristics, but even many economy cars have better audio isolation characteristics than typical rooms that lack deliberate soundproofing. Another advantage to using a car is that…well…it's quite mobile. So, even if your studio or "home base" is in a noisy area, you can simply drive your "sound booth" to any accessible, quiet, location when you're ready to record.

5.2.2. Preparing on Set

Even when planning to use ADR, it's generally helpful to take a best effort approach to recording dialogue on set. This raw audio can be useful as reference for editing prior to ADR, and can also be played back during an ADR session to help a performer recall the particular timing and rhythm they used when delivering the lines for the camera.

Before leaving the set, it is also a good idea to record several minutes of the natural, ambient sounds [Hack #55] (yes, all that noise you're actually hoping to get rid of!) at the location, with no dialogue or other movie-making related sounds, for use in the final mix. While these sounds can be distracting to the story if they are too loud, they can still be important to establishing the character of the location and solidifying the scene's environment in the viewer's perception.

5.2.3. Finding a Location

As mentioned before, it's best to drive your automotive ADR studio to a quiet location. It can also be helpful to have a rough edit of the scenes ready to playback (on a camcorder or any audio player) as a guide for the dialogue performance in the ADR session.

For recording, a digital recorder with a good microphone is best. Virtually all DV cameras record CD-quality digital sound when set to 16-bit mode. If you use a DV camera, make sure that it is not set to 12-bit audio mode when recording, because this setting results in a lower recording quality.

If possible, avoid using a camera's built-in microphone because they can sometimes pick up extra noise from the camera's tape drive. An external condenser (or shotgun) microphone is best, because that will cancel out sound that is not coming from directly in front of the pickup element, rather than a dynamic mic, which picks up sound from all directions.

Be sure to have one person on hand (other than the performer) who is responsible for running the recorder and listening to the audio while it records. This will allow the performer to focus on the dialog, and help ensure that you do, in fact, get a good recording. This person should also take careful notes regarding the timecode locations of each recording [Hack #11], so finding the good takes will be easier when capturing and editing the final scenes.

Finally, when delivering the dialogue, the performers should strive to use the same timing and emotion as was performed on set for the camera.

5.2.4. Editing Your Audio

In closing, here are a few tips that can help with synchronizing the ADR takes with the camera shots from the original set:

• Use your editing application's audio waveform display to show the audio wave on the timeline. This will help make it possible to align the audio and video visually.

• Use cue marks to tag important syllables seen in the video and the matching syllables in the ADR track.

• Use a short fade-in and fade-out on the ends of ADR tracks to avoid noticeable pops and clicks in the final audio.

• If an ADR track is too far out-of-sync with a character's on-set actions, consider cutting to a different angle to show another character listening to what is being said, or something else related to the dialog so that viewer never sees the discrepancy.

• Remember to mix in just a little of the ambient, background noise recorded on-set, to help establish the location's environment without obscuring the important dialog.

As with any creative process or technique, using and editing ADR will take practice to perfect, but hopefully, the ideas and tips presented here will help you on your way to creating crystal-clear dialogue for your projects.

Nick Jushchyhsyn