iZotope Ozone 11 Advanced

Ozone 11 builds on what was already a powerful and sophisticated platform with options including Stem Focus, the Clarity module and (shown here) Upward Compress in the Maximizer module.

Ozone still offers traditional mastering tools — but its AI‑fuelled options open the door to so much more!

iZotope’s Ozone, which first appeared way back in 2001, played a huge role in the ‘democratisation’ of audio mastering — at a time when DAWs’ in‑built plug‑ins were somewhat rudimentary, it was a powerful suite of software tools that anyone with a suitable computer and half decent monitoring could use. Of course, Ozone has evolved considerably since those early days but the latest version, Ozone 11, is the first major update since iZotope became part of the Native Instruments family. As with other recent versions, it’s available in three forms to suit different needs and budgets: Advanced, Standard and Elements. All are available for macOS and Windows, and they can work standalone or as a suite of AAX, VST or AU plug‑ins.

There are lots of options that could easily be described as ‘reverse mixing’ — or perhaps ‘magic’.

For a long time, Ozone required the user to have some understanding of the principles of mastering and how to apply them in practice. You can still apply such skills and understanding of course, but in recent years iZotope have been busy integrating ‘AI assistance’ tools that make it easier for less experienced users to benefit from Ozone’s deeper functions. This is particularly obvious in the Elements version: in this one, the processing is essentially ‘AI led’, and the user is offered a compact set of macro controls to customise the software’s recommendations. But my primary focus for this review will be the full‑fat version: Ozone 11 Advanced. While this also makes greater use of AI than its predecessor, the user is trusted with more control and it boasts an intriguing array of new features and modules. Ozone is still designed primarily with mastering in mind, but it’s definitely useful for more than that: in fact, there are lots of options that could easily be described as ‘reverse mixing’ — or perhaps ‘magic’, depending on your level of incredulity when Ozone does its thing!

Make It Clear

A new module in Ozone 11 Advanced, Clarity expands on functionality in the existing Stabilizer and Spectral Shaper modules, and it’s a similar concept to plug‑ins such as Oeksound’s Soothe or Baby Audio’s Smooth Operator. It dynamically adjusts the tonal properties of your audio in real time to produce a more appealing tonal balance or, in iZotope’s words, to “pull the blanket off” dull mixes but without sounding harsh. This is achieved by undesirable resonances being tamed and adapting the average response towards that of pink noise.

The Clarity module is a very effective tonal balance tool for Ozone 11 Advanced users.

Clarity operates only on the signal above 300Hz, but you can narrow the focus using handles in the real‑time frequency display. You can set the overall amount of tonal adjustment, as well as attack and release times for the processing, while a Tilt control lets you adjust the tonal balance of any adjustments for a darker (closer to a brown noise target) or brighter sound (nearer white noise). The different responses can be easily visualised on the display. With a mix that’s already well balanced, Clarity might apply just a touch of icing on an already tasty cake, but it can also go a long way towards rescuing a mix or recording that’s initially too bright or too dull, without the adjustments sounding forced.

Naturally, Ozone’s AI assistance can configure Clarity for you, but you needn’t rely on that. First, the module’s preset collection includes useful options intended to address specific problems, for example Mud Removal and Tame Harshness. But also, whatever the specifics of the processing algorithms themselves, the controls all feel precise and intuitive, making this module very easy to operate manually too. And since Clarity is also one of the modules that’s available independently of the Ozone ‘mothership’ (iZotope’s term for the main Ozone plug‑in), it’s also pretty convenient — and addictive too, as a very controllable audio ‘sweetener’ — for use in a mixing context.

Ozone’s Maximizer has always been a very capable tool for getting the final loudness of a signal exactly where you want it, and in the Standard and Advanced editions, a new Upward Compress control has been added to it. This allows you to boost quieter sections in the mix, and place more emphasis on those low‑level details. Provided that you don’t overcook things with this processor, it can be very effective. For example, applying only about 3dB of Upward Compress to a rock mix gave the track the greater sense of power, solidity and energy generally that I’d been looking for, and this seemed to be achieved without compromising the overall loudness or how transients and peaks came across. It’s a welcome addition.

All Ozone versions now include the new Vocal Balance option in the Master Assistant. The Master Assistant has been suitably trained to identify appropriate vocal levels and if it spots a problem when it’s ‘learning’ your audio, it will include the Master Rebalance module in the suggested signal chain. Set this module to target just the vocal stem, and then adjust the vocal level as required. You can, of course, make further tweaks yourself via the simple slider. However, if Ozone thinks the vocal level is already good, Master Rebalance is not applied and you just get a suitable tick of approval within the UI.

Ozone 11 brings further AI‑based assistance into the workflow with the new Vocal Balance slider within the Mastering Assistant display.

More Than Mastering?

As mentioned earlier, version 11 expands some of Ozone’s capabilities to make it useful well beyond conventional mastering. The Master Rebalance module, mentioned in passing above and introduced in v10, already allowed you to separate a stereo signal into four ‘stems’ (vocals, drums, bass and ‘everything else’) and adjust the levels. But remarkably, for Advanced users, that stem‑based processing has now been implemented within the majority of Ozone’s other modules, in the form of Stem Focus.

This can be engaged using buttons at the top left, allowing the whole signal chain to be switched between processing the full mix or, in real time, to dig within the spectral data and just apply the processing to the drum, vocal or bass. Want to hear additional compression only on the drums, EQ the bass, or apply a vintage tape effect to just the vocal? You can now ‘reverse engineer’ individual mix elements in precisely this way with Ozone. The only catch, really, is that you might need multiple instances of Ozone if you want to process both a stem and the full mix at the same time.

Standard and Advanced users gain a further ‘dig into the mix’ option. In addition to the stereo, left‑right or Mid‑Sides processing previously offered at module level, some modules now allow separate processing of the transient and sustain portions of a sound. And, of course, Advanced users can use this in combination with Stem Focus, meaning you could, say, apply EQ or exciter changes to just the transients of your snare, or different compression settings to the transient and sustain portions of your bass, or... well, you get the picture.

You can argue about the pros and cons of revisiting mix decisions in this fashion, and yes, of course it’s still a good plan to get things right at source, but it really is remarkable to see this functionality in operation, and I have to say that I found it very effective. When it’s simply not possible to revisit a mix project, these tools could well offer you a route to better results.

Among a host of other refinements included in this release, many modules now offer a ‘delta’ monitoring option (the ear icon located top left of the module window). This lets you hear just the changes — the difference between the original audio signal and the processed version — and it can lead you to some interesting insights, particularly when using EQ or dynamics modules, as it can make it much easier to spot if you’re pushing the processing too far.

In an effort to improve workflow, a number of modules have been treated to a bit of a UI facelift. This includes the Master Assistant, Low End Focus, Spectral Shaper and Maximizer. By the way, graphical tweaks aside, I love that Low End Focus module: if you often struggle with creating a controlled, well‑balanced bottom end in your mixes, you can quickly audition a range of presets that show you what various low‑end treatments might do to improve matters.

As shown here for the Low End Focus module, some of Ozone 11’s modules now provide the option for separate processing of the transient and sustain elements of an audio signal.

Eleventh Heaven?

So, is Ozone 11 mastering heaven? I suspect it will have less appeal to those who are happy with their high‑end analogue‑based mastering chain. But for those who are happy working in the box, and those for whom DIY mastering is the pragmatic option, Ozone 11 definitely improves upon what was already a tempting proposition.

Given its combination of power and depth, Ozone 11 Advanced could seem intimidating to anyone new to the mastering process, but iZotope’s integration of AI is starting to make a real difference in this regard — it can gently hold your hand while you explore mastering’s pure science and dark arts. What’s more, you have the option of starting with the compact, almost entirely ‘assisted’ Elements version, and then upgrading when you’re ready to go deeper down the mastering rabbit hole.

But while Ozone 11 Advanced remains a great mastering tool, it is now so much more than that. Its individual modules can be put to very good use when mixing, and it allows you to revisit many mix decisions that would otherwise be baked in. This is powerful, deep, high‑tech, sci‑fi‑style audio processing, and a lot of it bears a striking resemblance to magic!