Audio, Reviews

iZotope Ozone 6, stripped from undue features, best mastering tool around

Probably for the first time in history, a developer actually removes features from an application in response to user feedback. iZotope did just that with the Ozone 6 mastering solution. The result is a lean, mean mastering machine with looks to kill for and not one feature that gets in your way. Ozone 6 does come with a new module, though: a very effective dynamic equaliser. Ozone 6 can be used as a plug-in to your DAW or sound editor, or as a stand-alone mastering solution.

Sound projects usually start in a DAW (Digital Audio Workstation) or sound editor. You import a bit of audio, add some audio to different tracks, perhaps a software instrument or two and then the time has come to bounce — jargon for exporting your audio or music — your project. Before you bounce, there’s one final fine-tuning operation to be done: mastering your mix (the mix is the result of all your tracks added together). Mastering ensures each instrument (both software and real ones) and audio track (whether it be vocal tracks sung or spoken) sounds best in the end-result.

For example, if you’re mixing a song, you want to make sure there’s a good sound scape, a transparent stereo image. The voice of the lead singer might sound a bit harsh in some parts. The mastering application allows you to tone down the voice just a bit so it sounds well. In short, the mastering phase puts everything in sound-wise/musical perspective and makes the end-result sound perfect.

Ozone 6 stand-alone

For a long time now, iZotope’s Ozone has been one of the leading mastering modules for AU and VST capable DAWs but it was a rather complex app to use. It contained a few modules that don’t belong to mastering per se. Ozone 6 is a completely new version, rebuilt from the ground up. The only thing that still reminds of the older versions is the output quality and the power it puts in the hands of the sound engineer.

I’m not a sound engineer, far from it, but even people like me — let’s call us enthusiastic amateurs — can create a good sounding master with Ozone 6. iZotope provides an excellent tutorial on the subject and the app itself isn’t complicated to use. Version 6 is very user-friendly and extremely well designed.

Ozone 6 stand-alone

You can use Ozone as a mastering plug-in to — in my case — Logic Pro X, but now that Ozone 6 is a stand-alone app as well, it may also serve as a mastering solution for audio files that you receive from others in a more or less “finished” state. I found out that it will work its magic with more than just music files too. Especially the dynamic equaliser is a boon if you want to process specific frequencies. You can base your edits on a sound’s dynamic and spectral qualities as it changes over time with the dynamic EQ.

For example, I let Ozone 6 loose on a file containing sound from nature — from a park with a road close-by, actually. Needless to say the sound of birds tweeting was drowned in a cacophony of sirens, cars accelerating and slowing down, people shouting, etc. I could just have run the file through RX 4 Advanced — which I did for that review — and denoise the lot. For this review, however, I thought I’d see if I could use Ozone 6 to slightly muffle the background noise so that the tweets would be standing out more. After all, noise is sound too.

It turned out I could make the conversation of our feathered friends stand out more against the city noise, although not as clearly as with the Denoiser in RX 4 Advanced, of course. While this experiment of mine isn’t what you’d normally use Ozone 6 for, it shows that a mastering app’s usage scenarios aren’t necessarily limited to mastering a music score only.

The Ozone 6 features

iZotope let me review Ozone 6 Advanced, which has seven mastering tools organised in easy to insert modules, including Maximizer, Equalizer, Dynamic Equalizer (Advanced only), Dynamics, Imager, Exciter and Dithering. The Advanced tool furthermore gives you the ability to use all modules as separate plug-ins in your DAW or sound editor — in essence, for the price of one mastering tool you get seven functionalities.

Ozone 6 supports sampling rates of up to 192kHz and has extensive automation support. Its modules are modeled to analogue processing units, but combined with linear-phase precision. Nowhere is sound quality sacrificed for better performance in terms of speed or CPU power consumption. With Ozone 6 you’ll always end up with the best possible audio quality.

Ozone 6 all bands

The app as well as the plug-in also allow you to compare your settings with up to four history points. The stand-alone app offers In/Out fading and trimming, which is great when you’re quickly editing a score that must fit a movie, for example. In addition, it supports file export with automatic dithering and sample rate conversion, as well as third party plug-in support. It would be rather silly in my opinion but if you wanted to, you could add a NugenAudio SEQ-EQ module to Ozone 6!

The stand-alone app as well as the plug-in versions both have a dramatically updated interface with a whole new way of activating modules, with icons that tell you what they are in the blink of an eye. Overall, the new interface looks great and I found it doesn’t need much adapting to or learning . It is very intuitive indeed.

The Advanced version includes the Insight system as well as support for third party plug-ins.

In stand-alone mode, Ozone 6 allows you to master multiple sound files. Obviously and due to the labour-intensive nature of mastering, they can’t be active simultaneously unless you’re automating export for example. In that case, your machine will determine the maximum number of files that can be processed — my olde iMac had its hands full with one file.

As tradition wants it, Ozone 6 comes with a generous bunch of presets. There are three categories: Balanced, Heavy and Light. Heavy is for quieter mixes, Light for louder mixes. If you want to, you can import Ozone 5 presets, but not all of them will work the way you expect. Ozone 6 has some modules completely overhauled and while they sound better when using natively, the Ozone 5 settings may have to be adjusted to sound correctly too.

Ozone 6 stand alone fade in fade out

Some modules from Ozone 5 have disappeared altogether. The modules that survided — and which allow you to concentrate on mixing more than on adding effects — look different and some of the controls work just a little different than they used to, but the essence has remained. For example, the multiband modules (Dynamics, Exciter and Imager) still have up to fours bands and you can let Ozone 6 learn where to best put the crossfades.

Ozone 6 EQ modules

The ‘ordinary’ equaliser in Ozone 6 hasn’t changed much from the previous version, although I noticed one new filter type (Baxandall). Quality of output hasn’t changed either with this filter. Especially with the equalisers, I did find the new interface much more informative than the previous one. The ordinary one has eight bands to play with. Equalisers have three display modes: a spectrum view, a main view and an all bands view. The main view shows a tab per band. Clicking the tab reveals a deeper set of parameters applying only to that band.

Together with the ability to magnify sound (click-hold the band’s node then holding the Option key depressed) you can fine-tune each band’s sound characteristics. Effects can be very subtle this way. Equalisers be in Analog or Digital mode. In Digital mode, you can set the selected band to shift phases using a phase slider. Alternatively, you can set it to Surgical mode, which changes the filter curve to exact shapes — losing out on the musical quality.

The ordinary EQ also comes with a Match EQ button, allowing you to match the EQ to the spectrum or frequency response of another recording. This Match EQ feature is a digital linear-phase EQ that can use over frequency 8,000 bands for very precise matching.

Ozone 6 dither

The Dynamic EQ has four bands and sound-wise it works wonders when you want to reduce a specific frequency. It works the other way around as well, boosting a frequency, but as far as I could tell the reduction scenario just makes more sense.

Other Ozone 6 modules

The Dynamics module lets you shape the dynamic qualities of your mix across four bands. It processes compression, limiting and expansion. You can have this module work for you by selecting automatic gain compensation. This works well but it’s only available when all four bands are selected.

Imager lets you set the stereo image for up to four bands and has a polar sample and level vectorscope, a Lissajous scope and a correlation metre. You can choose from three displays: Crossover view, Stereo widths spectrum and Correlation View Trace.

The Exciter module is one of those modules that have been made a lot more intuitive to use due to the much improved interface. You can give up to four specific frequency bands a boost, using six different saturation types (warm, retro, tape, tube, triode, dual triode).

The Maximizer lets you boost the overall level of a mix without sacrficing dynamics or clarity due to iZotope’s Intelligent Release Control (IRC). In essence, it makes everything louder without introducing musical artefacts. There are four styles to choose from and three levels of IRC complexity. I couldn’t make IRC III work on my Mac in real-time without some serious ugly feedback. This is documented in the user guide where it says IRC III is very CPU-intensive as it is based on advanced psycho-acoustic models.

Finally, the Dithering module looks different but comes with iZotope’s MBIT+ Dither for the best possible conversion to different bit depths.


Ozone 6 is an exceptional mastering solution. It’s highly focused on mastering with no distractions from other filters or capabilities. Its Dynamic EQ is a perfect addition to decrease loud overtones or boost frequencies whenever the loudness of the specified frequencies are above or below a certain threshold. The quality of output when Ozone 6 is in the right hands, is typical of iZotope: near perfect. The stand-alone version is great for working independently from a DAW.

The only downside is that Ozone 6 does require an updated machine for comfort. Sample rates of above 48kHz made it difficult to work with modules in real time on my mid-2011 3.1GHz i5 iMac.


  1. I’m disappointed. I just bought it because I thought it would be even more amazing than T-Racks. I used the Maximizer, it did nothing. Same as the IRC. Hardly any effect. The EQ is cool but not $150 better than T-Racks’. I ended up just using a T-Racks compressor just to get it to sound mastered at all.


    • IT Enquirer staff says

      With all modules I achieved a clear effect but obviously nothing extremely loud or very silent, as that’s the sort of effects you should have achieved before mastering. Mastering AFAIK is making sure your audio sounds perfect across output media and from what I learned about it, the adjustments should be subtle. There’s a good intro to what mastering is here.


Comments are closed.