Tutorial: Matching Ambient Sound Between Clips in iZotope RX4 Advanced

This fall, iZotope released version 4 of its RX audio repair software. Along with RX4 Advanced comes a new module called Ambience Match. As the name implies, Ambience Match can be used to learn ambient or natural sound from one clip and synthesize it onto another clip. It's really useful for situations where you've had to record ADR, or where you've had multiple recording locations. 

Sound Issues in Indie Film Production

To test Ambience Match, I paid a visit to director Jason Prisk, who is putting the final touches on his latest indie film, Crimes and Mister Meanors (Figure 1, below). (You can hear Prisk's description of the film in the tutorial video above. It starts around the 0:36 mark.)

Figure 1. Jason Prisk's new "family adventure" film, Crimes and Mister Meanors.

When I asked him what kind of audio issues he experienced in production, Prisk said, "When you're doing an independent film, I think the better question is, 'What issues are you not encountering?' There's always something. We did a lot of this film outdoors. It doesn't matter how hard you try to pick a location that's going to be perfectly quiet. It just never is. There's always trains, cars, planes in a pattern somewhere. Trying to shoot in a downtown area, you constantly have sound issues. We're moving place to place, trying to move through scenes so quickly, that probably a third of the time, we didn't even both to get world tone, or room tone on location.

"Finding a tool that could fix that issue was huge. iZotope RX has the ability to very, very quickly solve a lot of the problems that we faced in post-production."

Enter Ambience Match

The first example Prisk describes of where Ambience Match played a critical role in getting consistent natural sound is the final scene of the movie, where one of the main characters, Uncle Bennie, holds an impromptu press conference on the outside steps of a municipal building. The scene was shot "on the street in Milledgeville, Georgia--which was doubling for Alexandria, Virginia in the film," Prisk says. "If you've ever shot on a street, you know that it's a constantly changing environment, and shot to shot, when you're trying to match those up [aurally], it's always different."

The clip below shows the scene before applying audio match. "You'll notice the changes as it goes along," Prisk says. "It sounds like it gets about half as loud after the first few phrases" that the Uncle Bennie character says.