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Izotope Ozone 5 Advanced

Mastering Software
Published March 2012
By Paul White

Izotope's do-everything mastering suite expands again, with a new Advanced version offering even more user control.

In Ozone 5 Advanced, the modules can be run within the main plug-in, as here showing the EQ, or as separate plug-ins, as shown in the other screen shots.In Ozone 5 Advanced, the modules can be run within the main plug-in, as here showing the EQ, or as separate plug-ins, as shown in the other screen shots.

Ozone 5 Advanced is the latest incarnation of Izotope's well-established mastering suite, and now comprises seven modules: Maximizer, Equalizer, Multi-band Dynamics, Multi-band Stereo Imaging, Meter Bridge, Multi-band Harmonic Exciter and Reverb. All are now available as separate component plug-ins, as well as within the master Ozone 5 plug-in, which combines access, routing and control for all the individual processing sections, and for the new Meter Bridge. The standard version of Ozone 5 has no Meter Bridge and no way to use the components separately, but otherwise offers most of the same functionality.

User-configurable meters provide additional display options showing spectrum, phase, vectorscope and level histograms, where you can, for example, see a history of compressor gain reduction scrolling by. Even the loudness meters have been upgraded to show levels according to BS 1770-2, EBU, K-System and True Peak standards, as well as RMS, with the various types available from within the Options section of the plug-in, along with other key settings and preferences. Module presets saved in earlier incarnations of Ozone will open in the separate component plug-ins of Ozone 5 Advanced, so there should be no backwards compatibility issues. The designers also claim to have improved the processing algorithms, including their analogue modelling and the new IRC III limiter used in the Maximizer section. The hybrid Reverb module has also benefited from an extensive makeover, with new room models added, while the Exciter can now emulate different types of analogue distortion based on tape, tubes and so on. Also on the upgrade list are new and easier-to-access presets, improved signal routing and additional controls. As the upgrade is so comprehensive, I'll look at each of the modules in turn.

Ozone's Layers

The new 3D scrolling Meter Bridge is only available in the Advanced version of Ozone 5.The new 3D scrolling Meter Bridge is only available in the Advanced version of Ozone 5.

Perhaps the most visually distinctive upgrade is the Meter Bridge, which provides a real-time 3D spectrogram that includes Freeze and Zoom modes as well as a 2D option. The display is interactive, so that the user can, for example, inspect gain values by holding the mouse pointer over the relevant section. It is also possible to monitor multiple audio stream spectrograms using Ozone Advanced's Meter Tap plug-ins. All you have to do is add Meter Tap plug-ins to the individual tracks or buses you wish to monitor, then select them for viewing in the Meter Bridge: each track's contribution is overlaid in a different colour. You can also meter information relating to the stereo image and mono compatibility of your mix with Lissajous and Polar modes, a stereo balance meter and a correlation meter.

The individual modules are mainly four-band processors, in which case the band boundaries may be adjusted by dragging them in the display. Input and output level controls, along with metering, are found to the right of the window, with an overall processing horizontal slider below. This standardised layout makes the modules very easy to navigate. Small buttons may be used to switch between two alternative meter scalings, with further buttons to select L/R or M/S metering where appropriate. Lock buttons may be activated to prevent further changes in this section.

Harmonic Exciter

Harmonic enhancers are by no means new. Aphex pioneered the concept with their Aural Exciter, where controlled distortion was applied to a filtered version of the input signal before it was dynamically processed and added back to the original dry signal. Ozone's take sees the audio split into four user-adjustable frequency bands that can be processed separately, using a distortion type selected from three tube styles (including a new triode emulation mode), tape-modelled saturation, or transistor saturation, with mix controls for each band. There's also an M/S processing option allowing different degrees of enhancement to be applied to the middle and sides signals before recombination into stereo. In addition to harmonic enhancement, it's also possible to fine-tune the timing between the four bands, rather in the manner of the BBE Sonic Maximizer, which can help preserve the attack transients of low-frequency sounds. An Oversampling button employs more accurate processing at the expense of CPU overhead (any process that creates distortion without using oversampling runs the risk of generating aliasing artifacts, though these are not always audible).

A meter at the top of the module shows the signal spectrum, or may be switched to display saturation: the spectrum is displayed in green, with the frequencies being affected by the saturation process shaded in black. Used carefully, this plug-in is able to add warmth, brilliance or density to a mix, although you have to take care not to overdo things and make the end result sound messy or harsh. You can probably afford to use more intensive processing on individual tracks such as drums, bass or electric guitar. I like having a choice of saturation options, though, and each has a distinctly different tonal character. 


Ozone's four-band Dynamics module is hugely versatile, especially in the Advanced version.Ozone's four-band Dynamics module is hugely versatile, especially in the Advanced version.

Again offering a four-band approach to processing, Dynamics comprises analogue-modelled compression, limiting, gating and expansion. Once more, there's an M/S option to allow different processing to be applied to the centre and edges of a stereo mix and, of course, there's improved metering. Compression can be hard, soft or variable-knee (the last in the Advanced version only), and there's an Automatic Gain Compensation system that makes it easier to evaluate the effects of compression without being misled by level differences. The metering includes histogram options as well as the Gain Reduction Trace meter mentioned earlier.

Each band has its own set of controls, which can be viewed at the same time if you select the global view, though I found this left the screen looking too busy with very small text. Selecting the Band view and then using the four band buttons, or clicking in the display to navigate between them, felt more comfortable to me, but at least you have the option. Gain and Mix settings may be switched to global or per-band mode, and there's also a wet/dry mix control for setting up parallel compression. A Linked Bands mode allows changes to be made across all bands by adjusting the settings of one band. The metering also includes a Dynamic Curve view showing both the input and output signals on two axes. Overall, I was impressed by the sonic transparency of this section used in a mastering context, as you can apply quite significant amounts of compression before the processing becomes in any way obvious. Operation was as straightforward as for any multi-band dynamics processor I've used before, and my overall impression was that it sounded very musical. Being a multi-band compressor, it is also useful for problem-solving such as reducing the level of popping or sibilance on individual tracks.


No less comprehensive is the EQ module, which can emulate both analogue filters and linear-phase filters, with the flexibility to combine both types. Version 5 sees the addition of new filter shapes in analogue mode, including flat (Butterworth), low- and high-pass, 'brickwall' low- and high-pass, and vintage shelving filters, the latter inspired by the Pultec design. In all, there are eight filter bands that can be set to bell, high-pass, low-pass, or high or low shelf, with a spectrum analyser available to view the stereo signal in L/R or M/S modes.

Ozone 5 Advanced's digital mode now features three selectable phase modes: Minimum, Linear and Mixed. Linear-phase filters give rise to equal degrees of pre- and post-ringing on transients, while minimum-phase algorithms apply only post-ringing, like analogue designs. Mixed phase mode enables each band to have its phase response adjusted between minimum phase (-1), linear phase (0), and maximum phase (+1). Note, though, that the maximum-phase filter places all ringing before the transient, making it the most obvious of the filter types.

In addition to its comprehensive manual EQ facilities, Izotope's Match mode is also included, so that one audio signal can be equalised to match the spectrum of another, using up to 8000 linear-phase filters. It is also possible to use the emulated analogue EQ for matching, and to my ears this often sounds more musical. The procedure is to capture a couple of audio snapshots from your source and reference audio files, then you click radio buttons to show which should be made to match which. Press Match and a matching curve is overlaid on the EQ display alongside the snapshot spectra, but this display may be disabled to conserve CPU resources. The Matching EQ works alongside the conventional EQ so it is still possible to apply conventional EQ to the matched sound, and as with most match EQ plug-ins, you can adjust the degree of matching and apply smoothing to the matching curve. One thing that had me fooled at first was that the Amount slider applies only to the conventional EQ settings, not the Match curve. I also experienced some odd behaviour in Logic when using the plug-in on a mono bus, where it still seemed possible to create different left and right EQ settings, which then caused the stereo image to shift — weird, as the bus was set to mono. Overall, though, this turned out to be a very capable EQ, with a very effective Match mode.

Stereo Imaging

The multi-band Stereo Imaging module offers the ability to apply different amounts of stereo image enhancement to up to four frequency bands, including adding different small delays to each band. Stereo recordings may be narrowed as well as widened, again with some visually impressive metering to display your results. My own Drawmer Masterflow mastering processor has a three-band stereo width page, and I find this very useful for narrowing the width of low frequencies that might otherwise sound wrong in mono, while subtly widening frequencies higher up the spectrum.

A scrolling correlation trace is drawn in real time, in addition to the semi-circular vectorscope. A mono-compatible Stereoize effect is included in the Advanced version only, for processing mono or very narrow stereo sources to create an artificial sense of width. Few details are given on how this works, but I suspect it uses the familiar system of complementary comb filters on either side of the mix. Being able to delay the four bands separately makes possible subtle realignment of the frequency bands and can add focus and definition to transients. This module is easy to operate and achieves the desired result with no fuss.


It's only a single-band algorithm, but Ozone 5's Maximizer is nevertheless a very transparent limiter.It's only a single-band algorithm, but Ozone 5's Maximizer is nevertheless a very transparent limiter.

As its name suggests, the Maximizer is there to make mixes sound louder while doing the least sonic damage. This is not a multi-band process and has no M/S processing capability, although the output meters can still be set to read M/S levels. Its limiters are designed to minimise gain pumping on transients, and in the three IRC limiting modes a Character control (in essence, a limiter speed) helps optimise the Maximizer's response to the source material, while a Transient Recovery feature, available only in the Advanced version, protects transients when limiting is taking place. Five modes are offered to tailor the process to the material being worked on and to the tastes of the user. The first three (IRC, IRC I and IRC II) are digital processes that rely on psychoacoustic principles to preserve clarity and transient definition when the Maximizer is being pushed hard; Hard and Soft modes offer more traditional analogue-style limiting, with the Soft algorithm achieving a smoother sound at the expense of some overshoot. When the Maximizer is set to Soft or Hard mode, the release time is adjustable, while in IRC mode you can activate and adjust the transient recovery feature and the release slider is replaced by the Character slider. An inter-sample detection option can be activated to avoid the possibility of inter-sample clipping.

The psychoacoustic IRC processing modes are said to be quite CPU-hungry, although they don't make too much of a dent in a relatively modern computer's capabilities. My early Mac Pro coped fine, with plenty of power in hand. Again, there's comprehensive metering, including spectrum and histogram views, with the option to work in stereo linked mode. Dither, when active, is applied to the signal independently of the Maximizer, and three dither types can be selected. There's the option to remove DC offset and even a dynamic display of bit usage. Although the limiter is fairly conventional in use, with the familiar threshold and maximum output level sliders, it certainly seems capable of hitting the peaks quite hard without causing any obvious detrimental effects.

Mastering Reverb

Reverb isn't an effect you'd always want to add when mastering, but it can certainly be a valuable tool.Reverb isn't an effect you'd always want to add when mastering, but it can certainly be a valuable tool.

The concept of a mastering reverb is a strange one: in an ideal world, reverb would be added to individual tracks prior to mixing. However, you occasionally get a track that simply sounds too dry, and then you need a specialised reverb to add life without making the mix muddy. Ozone's hybrid reverb combines convolution and algorithmic technologies; the early reflections are captured from real spaces using convolution, then married to an adjustable algorithmic reverb tail. In addition to a useful selection of room types, there's a plate mode based on the classic EMT 140 and an M/S option allows reverb to be added selectively and independently to the middle and sides components of a mix. This is particularly useful in a mastering context, as it allows the centre signals to be left dry if required, while still adding some 'reverb gloss' to sounds panned left or right.

A Crossmix control in the Advanced version adjusts stereo spread by controlling how much reverb is fed to the opposite channel, and pre-delay can be applied to the wet sound. The reverb types on offer are Room, Plate, Hall, Theatre, Cathedral and Arena, the last three being unique to Ozone 5 Advanced. Because the reverb tail is algorithmic, its decay time can be adjusted — with controls for high- and low-frequency decay — without affecting early reflections. High and low EQ controls are adjustable using drag points in the spectrum display. The window at top of the screen shows the signal spectrum by default, but there's a Reverb Character view that shows the shape of the reverb decay.

The control setup is extremely simple, and the only omission I noticed was the lack of a separate level control for the reverb tail. This means you can have a tail with no early reflections, but not just the early reflections without the reverb tail — which I would have liked to try. Auditioning the various spaces shows that the tonality of the reverb tail has been matched to that of the early reflections, and, with the exception of the plate, which has quite a subtle early reflections contribution, room character comes across strongly when the early reflection level is close to maximum. Used in moderation, the Room and Theatre settings add a welcome degree of life to a mix, although I suspect that most convolution reverbs would be capable of doing the job just as well. I do, however, welcome the M/S feature, as that allows a useful degree of control over which parts of the mix have reverb added to them and which don't. This module is particularly CPU-intensive, taking almost half a 'core' of my dual quad-core Mac Pro running at 44.1kHz.

In The Zone

The Stereoize option in the Imager process is new and exclusive to the Advanced version.The Stereoize option in the Imager process is new and exclusive to the Advanced version.

Ozone 5 Advanced certainly provides a powerful set of mastering tools, made all the more useful by the multi-band and/or M/S capability of some, although many users will find the basic Ozone 5 perfectly adequate, given the price differential. The 3D metering is nothing if not eye-catching, while the consistent layout of the modules is designed to make the user very familiar with the controls in the minimum of time. Izotope have a reputation for effective and good-sounding plug-ins, which Ozone 5 upholds, and they've included very useful tools that are often missing from competing mastering software, such as multi-band stereo width control and multi-band saturation. There are many good mastering products on the market today, but few offer so many facilities in such an approachable package, and the additional features and improvements will be welcomed by users upgrading from earlier versions.  


Perhaps the most obvious 'all in one' alternative is IK Multimedia's T-Racks, but there are good-quality software mastering bundles available from the likes of FabFilter, PSP, Sonnox, Universal Audio and Waves.

System Requirements

  • Windows XP Service Pack 2 or later, x64, Vista, 7; Mac OS 10.5.8 or later (Intel-based Macs only).
  • Supported plug-in formats: RTAS/AudioSuite, VST, MAS, Audio Unit, Direct X.
  • Graphics card: For use of the scrolling 3D spectrogram, Ozone 5 Advanced requires a graphics card that supports Open GL 2.0.
Published March 2012

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