iZotope RX 9 review

iZotope RX 9: What is it?

It’s hard to imagine the audio production landscape without iZotope’s RX repair and restoration platform. With each generation it’s sharpened to become a formidable tool for a huge range of tasks, straddling post-production, music recording/mixing and content creation with pricing schemes to fit many budgets. 

RX 9 is not a major update, but there are refinements and additions for existing users. For those coming to RX fresh, it’s an opportunity to experience this industry giant.

Choosing a version

RX is sold as three options: Elements, Standard and Advanced: the website hosts a clear comparison list. Both Elements and Standard offer tools to tackle most repair tasks. The pro-priced Advanced version modules are class leaders, with heavy-duty tools for all disciplines, particularly vinyl and tape restoration work. For post-production engineers, many modules pay for themselves. 

Beyond the Advanced version is the RX Post Production Suite which adds many other useful tools for film/TV work. A subscription edition, iZotope Music Production Suite Pro, is also available in annual/monthly formats.

iZotope RX 9: Performance and verdict

The spectrographic centrepiece of RX remains as flexible and revealing as ever, which along with the selection toolset provides the raw editing power this application is famous for. Even for those who’ve worked with it for years, the display provides new insights that expand our understanding of sound.

By allowing frequency as an editable component, alongside time and amplitude, the possibilities for editing are huge, even with simple tools, such as gain change. The ever-impressive range of selection methods, including harmonic series, coupled with the waveform/spectrograph overlays make short work of analysing audio for clicks, pops, hums and noise.

The sidebar module list remains unchanged from RX 8 and though the upper portion of the sidebar (Repair) is home to the stars of RX, the lower two are (Utility and Measurement) due some serious respect. The EQ is a 6-band-plus-filters slice of excellence and the trio of time and pitch options produce high-quality results. Some integrate with the Instant Process (attenuation, fades, gain) function which applies the last used setting to whatever you highlight, which is a time-saver on more laborious edit jobs. 

For the Advanced package, the Leveler and Azimuth modules are gems for post-production and restoration tasks respectively. Nestled between all these is the third-party plugin host that brings VST and AU collections.

Beneath Utility and Measurements is the History section, which is now (drum roll) expandable. This may not seem earth-shaking, but for those who have scrolled endlessly through tiny edits in previous versions, this simple improvement is welcome. 

The History list is also the host of a new feature, Restore Selection. This allows users to roll back processing for the currently selected area on the spectrogram, ie, it can be frequency-specific. This is an efficiency boost as it may often be quicker to undo what you don’t need processing than it is to make complex initial selections. As ever, the whole history is saved when the proprietary .rxdoc format is used.

Though the iconic spectrographic display, selection tools and utilities are hard to beat, the range and quality of modules in the Repair section really make RX stand out. This latest version brings new modes to a number of these, in both the Standard and Advanced packages, as well as a new algorithm for Dialogue Isolate (Advanced). 

This was already a powerful module, capable of preserving voices whilst cutting back a serious amount of background noise, particularly the stuff that a de-noiser can’t learn a profile for, but having tried the new algorithm on the same source there is a distinct improvement in artefact reduction. 

Further to this is a new mode for Ambience Match (Advanced) which allows noise environments to be applied to recordings, ie ADR or dialogue cleaned up with Dialogue Isolate/De-reverb, to maintain continuity. The new mode takes the static learned-loop basis and adds Movement and Randomness controls to mitigate overt repetition in complex backgrounds that may contain audible cues. Adding a threshold for the ambience learning also aids screening for foreground audio events that can cause a loop to be identified.

iZotope RX 9

Variations on a theme

At the heart of many of the modules lie machine learning aided algorithms. Some need cues in the form of sections of the noise they need to learn patterns from, such as the De-noise modules: Spectral, Voice and Guitar. Many also offer an adaptive mode where they are performing their own analysis. 

The Deconstruct module allows the user to split noise from tonal sounds and transients, and this is, to a large extent, what most other Repair modules do, whether that’s the transient removal of De-click and Mouth De-click or the noise reduction of De-rustle, De-wind and De-plosive. With this in mind, a user can experiment with modules not necessarily aimed at their source, such as using De-wind or De-plosive on a boomy drum mix.

For the all-important workflow, the Module Chain remains a great way to transport complex renderings across selections and files, while the batch processing is a now finely honed system for bigger jobs. Many of the modules are also installed as plugins, such as De-clip, De-click and De-hum, for tasks that are easier kept in the DAW, though the RX Connect plugin can also send an audio clip on a round trip via the main app for access to full repair shop.

RX 9 has one last card up its sleeve, the Spectral Editor for Logic Pro, an ARA extension that brings a spectral repair and the RX spectrogram and tools to a DAW. Hopefully, this will be rolled out for other ARA-compatible DAWs.

RX has offered good value through its three pricing tiers, which remains unchanged from RX 8, so new users should not hesitate to get on board if there is a repair/restoration need going unmet in their audio life. For existing users, this update feels a little light to spend out on, though iZotope are always canny with their loyalty offers. If post-production work, especially ADR, is your bread and butter then the Dialogue Isolate and Ambience Match improvements, coupled with the history/restore selection tweaks could really swing it. Either way, Logic Pro users are the ultimate beneficiaries here; other DAW users will have to live on in hope, for now. 

MusicRadar verdict: RX has been refined into an extraordinary platform and this update brings no major changes, but Logic Pro users will rejoice. Still the best.

iZotope RX 9: The web says

"For those coming to RX fresh, it remains an absolute powerhouse of professional audio restoration tools. These revisions make getting the job done with it even quicker and more effective."
MusicTech

iZotope RX 9: Hands-on demos

iZotope

Sam Loose Audio Engineer

Andrei Sora

EytschPi42

iZotope RX 9: Specifications

• OS: Windows 10, macOSX 10.14.6 - 11.6.
• SUPPORTED HOSTS: Logic Pro, Pro Tool 2021, Live 11, Cubase 10.5-11, Nuendo 11, Studio One 5, Reaper 6, FL Studio 20, Audition CC, Premiere Pro CC. 
• SUPPORTED FORMATS: AAX, AU, VST2, VST3 (64-bit only). 
• PRICING: RX Elements $129, RX 9 Standard $399, RX 9 Advanced $1,199 (upgrade and subscription options available).
• CONTACT: iZotope