Some years ago, MPEG published a very interesting article of Charles Maynes talking about his approach on the use of the worldizing technique:
For some of us in sound and music circles, “worldizing” has long held a special sense of the exotic. Worldizing is the act of playing back a recording in a real-world environment, allowing the sound to react to that environment, and then re-recording it so that the properties of the environment become part of the newly recorded material. The concept is simple, but its execution can be remarkably complex.
In Walter Murch’s superb essay on the reconstruction of the Orson Welles film A Touch of Evil, he quotes from a 58-page memo that Welles wrote to Universal to lay out his vision for the movie. At one point, Welles describes how he wants to treat the music during a scene between Janet Leigh and Akim Tamiroff, and he offers as elegant a description of worldizing as I can think of:
The music itself should be skillfully played but it will not be enough, in doing the final sound mixing, to run this track through an echo chamber with a certain amount of filter. To get the effect we’re looking for, it is absolutely vital that this music be played back through a cheap horn in the alley outside the sound building. After this is recorded, it can then be loused up even further in the process of rerecording. But a tinny exterior horn is absolutely necessary, and since it does not represent very much in the way of money, I feel justified in insisting upon this, as the result will be really worth it.
At the time, Universal did not revise Touch of Evil according to these notes, but the movie’s recent reconstruction incorporates these ideas. Worldizing is now a technique that has been with us for some time and will likely be used and refined for years to come.