Worldizing Sound

Walter Murch sound design concept for making sound “feel” more natural.

The sonic equivalent of photographic depth of field. Manipulating sound until it seemed to be something that existed in real space. This refers to playing back existing recordings through a speaker or speakers in real-world acoustic situations, and recording that playback with microphones so that the new recording takes on the acoustic characteristics of the place it was “re-recorded.” The concept is simple, but its execution can be remarkably complex.

Used in American Graffiti. Back in 1973, Walter Murch was working on American Graffiti and trying to create something new with the film’s Wolfman Jack sound material — commercials, hit songs, DJ rants. His task was to turn the soundtrack into a cohesive soundscape, to make every car cruising the city of Modesto, California a player in a citywide radiophonic symphony. The idea was that every teenage car in this town was turned to the same station, and, therefore, anywhere you went in the town, you heard this sound echoing off the buildings and passing by in cars.

In American Graffiti, recordings of the Wolfman Jack radio show were played through practical car radios and re-recorded with both stationary and moving microphones.

The practice of worldizing — and, I believe, the term itself —started with Walter Murch, who has used the technique masterfully in many films. However, it has received most of its notoriety from his use of it in American Graffiti and in the granddaddy of the modern war film, Apocalypse Now.

In American Graffiti, recordings of the Wolfman Jack radio show were played through practical car radios and rerecorded with both stationary and moving microphones to recreate the ever-changing quality of the multiple moving speaker sources the cars were providing. On the dub stage, certain channels were mechanically delayed to simulate echoes of the sound bouncing off the buildings. All of these channels, in addition to a dry track of the source, were manipulated in the mix to provide the compelling street-cruising ambience of the film. In Apocalypse Now, the most obvious use of this technique was on the helicopter communications ADR, which was re-recorded through actual military radios in a special isolation box. The groundbreaking result has been copied on many occasions.

Natural ambiance is needed. Digital reverb wasn’t going to do it. Worldizing it makes the sound “feel” much more natural.