iZotope RX 3 Advanced

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iZotope RX 3 Advanced is the latest incarnation of a versatile noise-reduction and audio-restoration suite that offers a comprehensive set of tools inside a waveform/spectral-editing interface. The update features a top-to-bottom UI redesign and adds powerful new modules for fixing audio problems as well as creatively manipulating sound. Most of the modules can also be opened as plug-ins in a DAW or other host.

The most significant aspect of the new UI is that you can now have up to 16 tabbed files open at the top of RX’s interface, and conveniently switch between them with a single click. Otherwise, the interface is conceptually similar to the previous version. It’s based around an editing window (mono or stereo) that lets you work with waveform and spectral data, and easily adjust the visual balance between the two. You also get a flexible set of selection tools, which let you grab and process anything from a full-length file to a tiny frequency range in a sample-level slice. You can also open third-party plug-ins from within RX 3, though they cannot be applied to frequency-specific selections. The standalone version supports AU and VST plug-ins, while the RX 3 plug-in supports AU, VST, RTAS/AudioSuite, and AAX formats.

A standard version of RX 3 has the same interface and all the essential audio-restoration tools from the Advanced version (Declick, Declip, Remove Hum, Denoise, and the amazing interpolation-based Spectral Repair), but with fewer adjustable parameters. This review focuses on the new features found in RX 3 Advanced.

Who Needs Reverb, Anyway? Probably the most talked-about module in RX 3 Advanced is Dereverb, which does just what its name says: removes reverb from audio (see Figure 1 on page 59). Its operation is based on algorithms that detect the ratio of reverberant-to-direct signal in the audio. First, you train Dereverb, letting it analyze the audio and suggest settings. It features a master control and four band-specific sliders that allow you to tailor the reduction based on the reverb’s frequency content. Pushing the main reduction slider in the opposite direction increases the reverb content detected in the signal.

As with any noise-reduction processor, overdoing it will make your audio sound unnatural, so the trick with Dereverb is to find the setting that removes as much of the reverb content as possible, without noticeably impacting audio quality. In my tests, it worked quickly and performed well in most cases, although when the reverb was really heavy, it was harder to remove it all. According to iZotope, some Dereverb jobs require several passes, and they suggest performing light denoising first to prep the file for Dereverb’s algorithms to work at their best.

While undoubtedly a useful tool for post-production dialog editing (matching ambience among disparate dialog sections), you can also use Dereverb creatively to get some otherwise unattainable effects. I used it to boost the natural reverb on a percussion track, which gave me dramatically different results from what I’d get by simply adding reverb from a processor.

Dereverb requires a lot of computing power. As a 32-bit plug-in within Pro Tools 10, it was unable to cleanly process the audio and it used up a lot of CPU. When I opened it in 64-bit Pro Tools 11, however, it worked fine. Interestingly, it also worked fine in 32-bit Digital Performer 7.

iZotope RX 3 Advanced debuts a spiffy new UI, along with some amazing new sound-manipulation modules.
Tear Down that Audio The Deconstruct module also provides unusual control over your audio: It separates the tonal and noise aspects by analyzing the harmonic structure (as opposed to Denoiser, which uses frequency magnitude). Its key controls are sliders for tonal content and noise content, which can be boosted or cut to give you control over the balance of the two components. Deconstruct has obvious noise-reduction uses, but it’s also great for subtly adjusting instruments that have significant noise components (such as changing the amount of breathiness on a flute).

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Dialogue Denoiser works in real time to remove steady background noise from dialog. I found it to be fast and effective. The processor can be run in Auto or Manual mode; in Manual mode, you can adjust the noise threshold for six different frequency bands.

One of the coolest modules in RX 2 Advanced is the Time and Pitch tool: In version 3, iZotope added BPM as an adjustable parameter for setting time stretches—in addition to percentage—making this tool much more musical. I was blown away by the quality of its tempo and pitch changes. For instance, I increased the tempo of a sax loop by 20 BPM and it still sounded natural. Pitch changes sounded great, too.

Pitch Contour makes it possible to set up pitch changes that happen over time. Designed with vinyl and tape restoration in mind, it allows you to correct for drifting pitch, which is often an issue in those applications. Its interface resembles a graph, with pitch (in semitones) on the vertical axis and time on the horizontal axis. You click in the graph to create a Node, which can be dragged up, down, and sideways and controls when and how much pitch change is applied at that point.

Unlike the pitch change in main Stretch and Shift mode, the audio slows down or speeds up, depending on the direction it’s shifted. That makes it possible to perform some amazing effects in which you speed up or slow down an entire mix at a precise point in time. At extreme settings, the Pitch Contour module allows for some super-creative audio mangling.

Other new features in RX 3 Advanced include a serious beefing up of the Spectrum Analyzer module and the addition of center-channel extraction to the Channel Operations module.

Prescription Filled All told, RX 3 Advanced gives you a deep and powerful collection of noise-reduction and audio-restoration tools, with some amazing sound design capabilities, several of which are unique to this product. Although RX 3 Advanced is an investment at $1,199, it’s one that is likely to pay dividends for a long time to come.

Michael Duke is a New York City-based music journalist and producer.


STRENGTHS Comprehensive collection of noise-reduction and audio-restoration tools in a single, well-designed application. Dereverb and Deconstruct are unique and powerful. Excellent new UI design. Conveniently tabbed files. Most modules can be opened as plug-ins. Spectral Repair and Time and Pitch modules are superb.

LIMITATIONS Advanced version is expensive. Dereverb is processor-intensive.

RX 3 Advanced, $1,199 MSRP
RX 3, $349 MSRP