RX Advanced is iZotope’s flagship audio-correction/fixing application. A couple of versions ago, the app became a true editor with the ability to record and edit audio and to fix, correct and adjust using sophisticated machine learning algorithms. As with all technology, the app continuously evolves and improves, and the latest version, RX 7 Advanced, is now capable of intelligently identifying vocals, bass, percussion and other instruments in a mix. In addition, RX 7 Advanced now also supports surround sound.

The RX interface gives users a synthesized overview of recorded audio, with the waveform in blue on top of the sound’s spectral information. In order to understand exactly what you’re fixing or editing, you need to understand that the waveform only represents the sound’s volume, whereas the spectrograph shows the sound’s energy, i.e. the different frequencies, harmonics, etc. You can process a complete file or selections of it.

With RX 6 Advanced, you could change music in ways that sound perfectly natural — not a hint of having done it in software. With RX 7 Advanced, you can do the same to dialogue. In fact, RX 7 Advanced is so good at correcting imperfections in recordings, in many cases you will be able to use it as a faster and cheaper alternative to ADR.

RX 7 Advanced with Dialogue: an Alternative to ADR

iZotope RX 7 Advanced's Dialogue Contour module

iZotope RX 7 Advanced’s Dialogue Contour module

I quickly realized this when I experimented with the Dialogue Contour module. When I’m recording a video tutorial for some app, I have a tendency to increase my voice’s pitch as I approach the last part, but then realize I still need to add a closing thought. Often, that turns out to be totally uncalled for — at which point I find myself with an end that sounds like it’s a question.

The only fix so far has been to start over again or record a voiceover. That’s hard to synchronize with the rest of the video without software like VocAlign or Revoice Pro. With RX 7 Advanced’s Dialogue Contour, however, I can now just lower my voice in the module, and you won’t hear that it was not recorded that way, no matter how hard you try.

With RX 7 Advanced, you can also isolate or remove dialogue or vocals from music. When in a video of a restaurant with background music, for example, the dialogue is hard to hear, you can fix that with Music Rebalance. This also allows you to create instrumental (or acapella) versions of songs by removing the vocal elements and isolating the vocals from the background music. I had my doubts about this, but after trying it out myself with different settings, I am truly astonished that it works so well. I could even isolate Cecilia Bartoli’s voice from the violins in an aria on The Salieri Album. Admittedly, with the default setting there was a tiny bit of bleeding from those violins in her voice. But a bit of experimenting with the slider delivered a pure vocal signal.

De-Reverb is a module that has been available in RX Advanced for some time, but now there’s also Dialogue De-Reverb for removing unwanted reverb from dialogue clips using an algorithm optimized for a “spoken signal”. I tried that with a recording of an announcement over the intercom by a museum guide in a cathedral. That didn’t work because the signal was 99% reverberation. However, speaking myself in a microphone in that same cathedral worked much better than I could have imagined. This module, too, could be used in place of ADR.

Surround Sound

RX 7 Advanced now also supports 7.1.2 multichannel surround sound. It lets you work on multichannel projects by toggling between all channels in one view or displaying a summed view. You can also turn individual channels on and off, summing only the ones you want to work on.

Finally, iZotope’s RX 7 Advanced has assistive audio technology. This module is an intelligent repair tool that can detect noise, clipping, clicks, and more. It’s designed to speed up correction and edits. All you need to do is select the type of material (music, dialogue, other) and let RX 7 Advanced analyze the audio. The Repair Assistant then offers different suggestions for processing, using multiple modules, as well as three different intensities for each.

Your task is reduced to reviewing and auditioning, hitting Render, and letting Repair Assistant perform its magic.

I found the Repair Assistant to be really helpful with certain audio files and less so with others. Unfortunately — and as far as I could see — there’s no fixed rule to determine whether or not files are suitable to run through the Repair Assistant. The only rule I could deduce was that, if the audio has many sudden, unexpected artifacts that you can’t categorize as noise, clipping or clicks — and certainly when they sound like they’re really part of the signal you want to rescue — Repair Assistant sometimes isn’t going to cut it. Yet. I expect it to keep improving in future releases.

Insight 2

Besides RX 7, iZotope also upgraded its audio analysis tool, Insight. Insight 2 works in tandem with an iZotope plug-in, Relay, that allows you to monitor the interaction of two or more tracks or channels with the track you’re analyzing. If you insert an Insight 2 instance on the Master track, you can analyze up to eight different tracks upstream.

Insight 2 has new features as well. For example, the Intelligibility module allows you to measure whether your dialogue mix holds up in different listener environments. With the Intelligibility meter inserted on the master track, you can ensure that a dialogue is clearly understandable in low, medium and high noise environments. How those are defined remains somewhat obscure, although it does work as you’d expect. The meter requires that a Relay instance, which is inserted on a track or bus that feeds into the master output, be selected as the Source instance.

Another module that can tap into the Relay feature is the Spectrogram (2D or 3D), which provides a spectral representation of audio varying over time, allowing you to analyze individual elements within a mix. It can display data for up to eight sources simultaneously by selecting Relay instances in the source selection menu.

As with RX 7 Advanced, Insight 2 supports surround sound. For example, you can monitor the loudness of your surround sound mixes with support for Dolby Atmos 7.1.2 track configurations, but you can also monitor the surround sound field with a surround scope that shows the amplitude of surround channels. The Surround Scope not only monitors the phase relationship between neighboring audio channels, but also displays an alert when there is a negative correlation or phase cancellation taking place.


The RX 7 Advanced upgrade focuses on the human voice in both musical and noisy environments. It succeeds brilliantly at extracting vocal signals for you to manipulate. The vocal capabilities of RX 7 Advanced are so good that you can use RX 7 Advanced to fix dialogue instead of performing ADR.

Both RX 7 Advanced and Insight 2 now support surround sound, which makes them very suitable for cinema and video. Combined with the rather spectacular results you may expect from the machine-learning algorithms, there are now numerous cases which you don’t really need an experienced sound engineer for anymore.

In short, both apps deserve at least a closer look — a demo download is available — after which I think you will find them both must-haves.