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Tutorial: Matching Ambient Sound Between Clips in iZotope RX4 Advanced

How to use the Ambience Match natural sound-matching feature in iZotope RX4 Advanced to fix uneven ambient audio across multiple clips and scenes, using examples from Jason Prisk's new indie film, Crimes and Mister Meanors.

Ambience Match and ADR

So there's one example of how Ambience Match can quickly improve a scene with major inconsistencies in its ambient sound. Let's look at another example of how Ambience Match can address audible inconsistencies created by ADR, or Automatic Dialogue Replacement. The clip below shows a scene from early in the movie where Jake, the main character, and his friend Pat are walking on the National Mall in a scene shot on location in Washington, DC.


As you can hear during the cutaway to the National Archives, the ambient audio drops out almost completely. During the on-location shoot, Jake said his scripted line, "The National Archives?", before the crew realized that the name of the building (as etched into its facade) is "Archives of the United States." About a month later during a shoot at a different location, the crew captured an ADR bit of Jake saying the corrected line in an alleyway, creating the audible inconsistency heard during the cutaway.

"So, we have a hole," Prisk says, "with no ambience, and then we have the wrong ambience," as shown in RX4 in Figure 7 (below).

Figure 7. Ambience issues created by ADR as represented in RX4. Click the image to see it at full size.

In the previous section, we recommended using a segment with no dialogue to learn and capture the ambience. "Actually," Prisk says, "RX does a pretty good job of removing the dialogue and finding the ambience from it." So, if you don't have a place in your clip where you can grab ambience-only audio to learn, you can still create a match.

We'll try it with this scene, making a selection with dialogue in it, setting our In and Out points at the 1.7-second and 3.2-second marks of the clip, respectively, and applying it to the ADR section that follows (roughly) the 4.0-second mark of the clip to the 8.5-second mark, with a little bit of overlap on both sides to make sure we apply it to more of the clip than necessary, rather than less. So, again, make your selection, choose Ambience Match, click Learn, then click Process.

You can hear the affect of Ambience Match on this scene in the clip below:


As you can hear, Ambience Match "filled in the hole perfectly," Prisk says, "and I don't think you'd ever know that that ADR was shot anywhere but on the National Mall."

Ambience Match is just one of the new modules you'll find in iZotope RX4 Advanced. Leveler will help you automatically balance vocals, dialogue, and voiceovers. The Loudness module will make sure that your mix complies with network standards, and EQ Match will match the equalization from one clip onto another.

iZotope RX4 is available now from