iZotope RX12 Advanced

The new Scene Rebalance tool, which does for film sound what previous (and now improved) stem‑splitting tools did for music.

Since RX11 came out, there’ve been huge leaps in AI‑based audio repair and separation tools. iZotope’s boffin’s have now delivered their reply — can RX12 reclaim its crown?

iZotope don’t rest on their considerable laurels — their boffins beaver away constantly, finding clever new ways to improve their products, both in scope and in depth. RX, the company’s well known and highly regarded ‘toolkit for audio repair’, exemplifies this approach perfectly: an updated and enhanced version seems to be released roughly every two years. For example, the last two versions, RX10 and RX11 came out in late 2022 and mid‑2024, respectively.

Now, after another two years of complex R&D, RX12 is here — and it’s a timely release, since significant progress in the neural net field over the last few years has enabled competitors to leapfrog some of RX11’s capabilities. So while RX12’s brand‑new features may catch the headlines, it’s just as important that several tools have been completely rebuilt and significantly improved, the majority benefiting primarily from iZotope’s expanding expertise in machine‑learning and neural‑net technologies. Below, I’ll take you through exactly what RX12 brings to the party, and consider whether it still represents the benchmark in audio repair and restoration.

Versions & Tools

As usual, RX12 is available in three forms called Elements, Standard and Advanced. The flagship version, Advanced, contains all of RX’s 90‑plus tools, plug‑ins and standalone processing facilities, while the first two editions contain selected subsets at commensurately lower prices. The Standard version retains a very comprehensive set of over 70 tools and plug‑ins, essentially lacking the newest additions and most of the modules focused specifically on professional film and TV applications, although it does retain the Dialogue Isolate tool.

In contrast, RX12 Elements contains a very small subset of six relatively basic — but still capable — noise‑removal tools. Both the Elements and Standard editions can, of course, be used as starting points, with upgrade paths available to more capable RX versions should that become desirable. I was invited to review the Advanced edition, so that I could evaluate all the developments now on offer, but I’m conscious that not everyone will need this ‘full fat’ version, so I’ve included a table in the online version ofwithin this review (https://sosm.ag/izotope-rx12) to make it easy for you to see what tools and facilities are or aren’t included in each version.

The music stem splitting tool can now display all stems on a single page of the GUI, rather than in separate tabs — a move that facilitates considerable workflow improvements.

All three editions of RX12 benefit from a GUI refresh that makes them look a little more modern and, I think, attractive. But anyone familiar with previous editions should be pleased that it retains the same overall configuration and workflows that we’re used to. For instance, iZotope’s release notes flag as a major update a larger spectrogram screen at the heart of the user interface. It’s certainly there, and to be welcomed, but if I’m perfectly honest it’s probably not something I’d have noticed without the prompt! One thing I did notice very quickly, though, is a new monitor volume slider control in the top right‑hand corner: this makes it easy to adjust the volume when critical listening, and is a very handy addition, especially if working on a laptop without an external interface.

Many of the improved and rebuilt tools seem to work faster and more precisely, too, without sacrificing any audio quality. Another welcome addition to a lot of the individual tool windows is a new button with an ‘ear’ symbol located alongside the Preview/Bypass/Compare buttons. When previewing the tool’s processing, selecting this ear button switches the monitoring to reveal what is being removed — the ‘delta’ or ‘difference signal’, if you like — rather than the processed result. In most cases, this makes it far easier to hear when the processing is optimised, because it’s easier to check that the algorithm isn’t throwing away anything important, and while some tools had such a facility built in, it’s great that to have a common approach on the different tools. So that’s a very welcome addition.

A major update, in the form of another new button alongside the preview buttons, affects RX12’s three stem‑splitting tools. Labelled ‘Stem Split’, this button activates a new ‘Stems View’ mode within the spectrogram display, where the split output stems are now time‑aligned above each other in the same spectrogram. It’s a very big workflow improvement compared with the previous setup, in which the split elements appeared in separate tabs. More on that side of things below.

A couple of other worthy but perhaps less significant updates include a new search facility to find specific processing modules...