Review: iZotope Ozone 6

A makeover and more for a mastering mainstay
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A makeover and more for a mastering mainstay

With the release of Ozone 6, iZotope has further refined its suite of mastering tools and made significant additions—and subtractions. The company has given the program a massive makeover, both in the GUI and under the hood, providing users with even more power and control over audio than in previous versions.

Fig. 1. An updated GUI and analogmodeled filters are just a couple of the improvements found in Ozone 6 Advanced. The program comes in two flavors: Ozone 6 Advanced (see Figure 1) and Ozone 6. As with other iZotope software, the Advanced version offers significant advantages but costs more, although both versions offer a great deal of flexibility. In this review, I’ll refer to both versions as Ozone 6; when a feature is only available in Ozone 6 Advanced, I’ll point it out.

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Ozone 6 is a multiprocessor mastering plug-in that now also runs as a standalone application. (More on that shortly.) Designed to be an all-in-one mastering solution, it features two EQs (three in the Advanced version), a multiband dynamics processor, a multiband exciter, a multiband stereo imager, and a Maximizer (limiter) module, all of which can be used simultaneously. Ozone 6 provides a wide range of presets, both global and for individual processors, as well as a full-featured dither section.

Fig. 2. At a glance, you can see the GUI changes between Ozone 5 (left) and Ozone 6 (right). Now you can access up to six modules at a time and re-order and solo them as needed. Ozone 6’s user interface has changed considerably since Version 5. In the comparison in Figure 2, you’ll see Ozone 6 Advanced has more of an integrated look; many of the numerical displays are bigger and easier to read, and you’ll find more icons in the GUI. It’s definitely easier on the eyes.

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Beyond the cosmetic changes, Ozone 6 functions differently than its predecessor in a number of ways. Gone are the module-specific sliders and activation buttons, replaced by a flexible workspace called the Processor Module Browser, which makes it easy to access up to six modules at a time. Once you have modules activated in the browser, you can click-anddrag them side-to-side to change their order in the signal chain. (In previous versions, the order was fixed.) Each module has an on/off switch and solo button, which makes it easy to listen to how your mix sounds if you remove a processor.

Each module has its own gain meter that shows how much you’re boosting or cutting, giving you an at-a-glance view of how the various components are affecting your signal. Because only one module-editing window can be open at a time, having the meters along the bottom is helpful for keeping the big picture in mind as you work.

A new Auditioning Section, located under the Master Input and Output faders, conveniently centralizes a number of controls that were previously spread around the GUI. These include the Bypass button and an ear icon that turns on the Auto-Match gain feature (previously called Automatically Match Effective Gain), which adjusts the bypassed signal to the same level as the processed one. This makes it easier to judge the impact of the processing you’ve applied, because you are comparing with the original at the same level, avoiding the louder-sounds-better effect. There are also buttons for putting your file into mono, for swapping channels, and to turn on and audition dither.



A few Ozone 5 elements were left out of version 6. The most notable casualty is the reverb module. According to iZotope, the decision to remove it was based in part on feedback from users, both professional and amateur, who said it was the least-used module. iZotope also wanted to de-clutter the interface and underlying code for Ozone 6.

Although reverb is used far less often in mastering than EQ and dynamics processing, I’m sure some users will lament its removal. In practicality, though, it’s not a big loss; if you’re using Ozone as a plug-in, you can insert a dedicated reverb plug-in before or after it. If you’re using the standalone version of Ozone, you can bring in a reverb via the third-party plug-in feature.

You will also notice that the Dynamics module no longer includes gating functionality. Again, iZotope felt that part of the module was less important, so they removed it to decrease clutter and simplify operation.

Also gone from Ozone 6 are the Global Amount Control and Module Amount Control sliders. In previous versions, these allowed you to reduce or increase the amount of processing, either globally or for each individual module, which was a fast and easy way to experiment with processing levels. I found these controls to be very useful, so I’m disappointed that they didn’t make the cut.


Fig. 3. In Standalone mode, you can load and process multiple sound files individually. Both versions of Ozone 6 now run as a standalone application as well as plug-ins. The standalone version (see Figure 3) offers all the processing of the plug-in, plus it lets you load multiple files and process them separately. Imported audio files show up as tabs near the top of the standalone GUI and can be clicked and dragged to change their order. Underneath the tabs is a waveform display that shows a single track for both stereo and mono files.

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Transport controls are provided, including Play, Stop, Pause, Previous Track, and Next Track. You can also turn on looping and easily set a loop range by clicking and dragging in the waveform display. In addition, you can set start and end points for each track, as well as add fades.

A very useful addition to the standalone version is the ability to host third-party plug-ins. Although Ozone 6 is quite comprehensive, you have the option to integrate your favorite non-Ozone plug-ins into the signal chain. Ozone 6 has six module slots, which you can fill with any combination of Ozone and third-party processors.

Ozone 6 Standalone is not designed to be the final stop in the mastering workflow, though, because it doesn’t let you adjust the time between tracks, nor listen to song-to-song transitions. You cannot export a CD image or DDP image from it, just individual song files or a global export of all the songs as separate files. As a result, you’ll need a CD authoring program or 2-track editor to handle the sequencing and final export if you’re working on an album.



Mastering processes are often aimed at specific parts of the frequency range in order to address an imbalance without causing too much damage to other frequencies. The new Dynamic EQ module in Ozone 6 Advanced does just that: It is a 4-band EQ that functions similarly to a multiband compressor, except that you can dial in narrow frequencies with each band, giving you much more precise control while leaving large swathes of the frequency range unaffected.

For example, there might be certain spots in a mix where the vocalist’s voice gets a little harsh, and you could set the Dynamic EQ to cut at the harsh frequency only when it exceeded the threshold you set, therefore minimizing the amount of processing to the master.

The Dynamic EQ also has an Inverse Mode, which allows it to act more like an expander. Let’s say that you wanted to bring out the kick drum more, but didn’t want to use a standard EQ to do it. You could set the Dynamic EQ to Inverse Mode to boost in the kick’s frequency range, and with the threshold properly set, it would only process when the kick hit.

Additionally, you can work in stereo or M/S mode, which gives you an even greater ability to target specific elements of a stereo mix. What’s more, the Dynamic EQ can be opened as a dedicated plug-in (if you have Ozone 6 Advanced), so it can also be useful in mixing applications.

Since Dynamic EQ is a new type of hybrid processor, I wasn’t surprised to find that it was harder to use than processors I’m used to. Be prepared to experiment in order to find what you can and cannot do with it.

The Dynamic EQ, Equalizer, and Post Equalizer all have additional analog-modeled options in Ozone 6. These include Baxandall filters in the low and high shelves, Proportional Q (APIstyle), and peak and bandshelf options in the Bell filters. When you select one of the filter types within a band, the icon above it changes to the appropriate shape, which is a helpful touch and a good example of the subtle GUI upgrades I referred to earlier.

As for the new filters themselves, they give you a lot more options, as you now have multiple choices for each EQ type. The analog-modeled filters sound very good, and I was especially impressed with the Baxandall low and high shelves.



Presets have been completely revamped. The preset browser is now a separate window, which is more convenient than in Ozone 5, where it opened up on top of the main screen.

The preset collection is very important in Ozone, because a significant portion of the people using the program are not experienced mastering engineers, but home recordists who are engaging in DIY mastering. For that group, having presets as starting points is very helpful.

As in previous versions, Global Presets are comprehensive settings that utilize multiple modules and individual processors. Within the Global category, things are quite different from previous versions. All the presets have descriptive names like Control Dynamics, Emphasize Bass, and Increase High End. They’re organized into three categories: Balanced presets provide “standard” mastering levels; Heavy features aggressive processing; and Light provides less processing.

The Global presets are very useful, but there are no genre- or instrument-specific presets, and the Broadcast, Special Effects, or Utility presets that were in Ozone 5 are gone. I miss those, as they helped me quickly zero in on appropriate settings. However, if you have Ozone 5, you can upload the presets into Ozone 6: iZotope made sure the Ozone 5 presets sounded as good or better than before when opened in version 6. Some will sound different, though, in situations where features were removed, such as gating and reverb.


Clearly, iZotope has put a lot of thought into this new version and took the somewhat risky path of removing pre-existing features, such as the reverb module. The new GUI is definitely easier to work with and will be much appreciated when working with the software for long hours. The new Auditioning section is a useful one-stop-shop for checking your mix in various ways.

The standalone version provides a whole new way to work in Ozone, and its multiple-song capability is particularly handy for album projects. The new analog modeled EQ filters add variety. And for Ozone 6 Advanced users, the Dynamic EQ is an exciting new processor with a lot of potential applications. Both Ozone 6 Advanced and Ozone 6 significantly improve on their predecessors, which were pretty darn good to begin with.

The Undo History is perfect for making comparisons.Quick Tip: Use the Undo History to Compare Settings

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Ozone 6’s unlimited Undo History is a powerful feature. If you want to compare two or more different settings on a particular module (for example, the sound of analog-modeled vs. digital EQ filters), it's easy to do so. First change from one setting to the next in order to write them into Ozone’s history memory. Then, click on the History button at the bottom of the Ozone interface, and a separate window will open showing all the changes you've made. As the song plays, click between the different settings for an easy comparison.


Change the stereo width of your track using the Imager module.Quick Tip: Widen Your Mix with the Imager

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If you’re working on a mix that feels a little too squashed to the center, you can use the Imager to widen it: Open it and raise each band slider to around 50. Next, turn on the Stereoize feature and slowly raise its slider until you hear your mix open up. Experiment with the levels of the various bands as well as the Stereoize slider until you're satisfied. Turn the Stereoize button off periodically for a reality check, and check your mix in mono. As a rule, make sure the correlation meter (the vertical meter that goes from -1 to +1) stays between 0 and +1.

Ozone 6 vs. Ozone 6 Advanced

If you’re wondering which version to choose, here’s a rundown of the differences. From a module standpoint, the only difference between the two is the Dynamic EQ, which comes with the Advanced version. Otherwise, all modules are included in both versions. However, only Ozone 6 Advanced gives you component plug-in versions of all of the modules.

Ozone 6 Advanced also comes with a separate metering plug-in called Insight, which offers advanced metering options such as spectrogram, spectrum analyzer, loudness history, and peak and loudness levels. If you're using the standalone version of Ozone 6 Advanced, you can open up Insight as an AU plug-in using the third-party plug-in feature.

Dynamic EQ. Standalone version with multi-song capability and third-party plug-in hosting. New GUI. Auto-Gain. Analog-modeled EQ. Insight Plugin (Advanced version) offers plentiful metering choices. Individual Module Gain Meters.

Module Amount Control sliders and reverb removed. Genre- and instrument-specific presets no longer included. No way to create a CD image or DDP image from standalone version.

Ozone 6: $249 (upgrade $99)
Ozone 6 Advanced: $999 (Upgrade from Ozone 5 Advanced: $299; from Ozone 1-6: $750)

Mike Levine is a musician, producer, and music journalist based in the New York City area.