How GPS voice-overs work.

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Sept. 29 2009 4:00 PM

Voice in the Machine

How GPS voice-over recording works.

Bob Dylan. Click image to expand.
Bob Dylan

Bob Dylan, one-time voice of a generation, is allegedly mulling offers to become the voice of satellite navigational devices. The default for GPS audio is anonymous and generic, but celebrities like Dennis Hopper and Mr. T have recorded alternative tracks. How do such voice-overs—which contain a seemingly infinite number of specific directions—actually get recorded?

With a simple script. Most popular portable navigational systems work by mixing and matching just 59 sound clips. Some are numerical ("100," "200," "400"), others imperative ("Stay in the right lane"), and still others declarative ("You have reached your destination" or "Recalculating"). Navigational systems that are built directly within the dashboard of the car (called "in-dash" systems) tend to be more sophisticated and can incorporate hundreds of additional words—like street and town names. (These rely on text-to-speech technology rather than prerecorded phrases.) Settings vary by manufacturer and model, but the core group of commands remains the same.

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The recording process is straightforward and should take no longer than a few hours. Celebrity recordings are usually handled in a studio, with a director-manager guiding the talent through the script, ordering retakes, and identifying appropriate spots for personality or humor. (Mr. T will call you a "fool" if you miss a turn.) Many directions are recorded as complete phrases or clauses. For example, "Go right on the roundabout" is a single clip. But multistep commands such as "At the second right, turn left" are amalgams of two or more clips—in this case, "At the second right" and "turn left."

Professional voice-over artists, recruited to impersonate celebrities or play characters, often record and edit on home equipment, then e-mail the collection of audio files to a company that integrates them into the system and prepares them for commercial download. Some devices even allow consumers to record their own voice-overs. But most drivers don't want to listen to their own navigational voices—especially since they can opt for a sultry Kim Cattrall track instead. Celebrities are recruited because their voices are either famously pleasing (Burt Reynolds) or iconic (Hopper). As of yet, no A-lister has recorded a GPS voice-over. Dylan would be the first.

Got a question about today's news? Ask the Explainer.

Explainer thanks Will Andre of NavTones and voice-over artists Joe J. Thomas and Thomas Bromhead.

Eric Hynes is a New York-based journalist and film critic.

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