iZotope Ozone 4 (Mac/Win) Review

Jun 1, 2009 12:00 PM, By Michael Cooper

A FEATURED-PACKED MASTERING PLUG-IN AT A MODEST PRICE

Ozone is widely regarded as the cost-effective stereo mastering solution for the masses. The software plug-in supports RTAS, AudioSuite, VST, MAS, Audio Units, and DirectX formats, and combines six independent processing modules: paragraphic equalizer, mastering reverb, loudness maximizer (with dithering), multiband dynamics, multiband harmonic exciter, and multiband stereo imaging.

Ozone 4 adds dozens of new features and workflow refinements to earlier versions. Additions include mid-side processing, parallel compression, new Maximizer and Exciter modes, automatic gain compensation, and a new Preset Manager with more than 50 new presets. You also get MacroFaders that adjust several parameters at once and a bevy of new meters.

Ozone features 64-bit processing throughout and incorporates both analog modeling and digital linear-phase algorithms. It supports sampling rates up to 192 kHz. I reviewed Ozone 4.03 as an Audio Units plug-in in Digital Performer 6.02, running in Mac OS 10.5.4 on an 8-core 2.8 GHz Mac Pro.

The Big Picture

Ozone opens with a view of its new, detachable Preset Manager, which organizes 140 factory presets inside folders according to music genres and various applications (for example, to use on individual instruments). Use a preset as a starting point for mastering or select the default setup to null all settings and start from scratch.

As you select each of Ozone's six modules in turn, their controls and meters are displayed alone in the GUI. Three of Ozone's six modules offer multiband processing. You can split the dynamics, harmonic exciter, and stereo-imaging modules into as many as four frequency bands and adjust the bands' crossover points. This allows you to, for example, compress only the bass frequencies, add harmonics to just the midrange, and widen the stereo image solely for the highs.

Four of Ozone's six modules (all but the stereo imager and maximizer) can be set — independently of one another — to process either the stereo or mid and side (M-S) channels of your mix. The mid channel comprises everything that is panned to the center of your mix (typically, kick drum, snare, bass, and lead vocals). The side channel contains all elements of the mix that are dissimilar in the left and right channels, such as hard-panned instruments and reverb returns.

You can use M-S processing to compress only center-panned tracks (the mid channel), for instance, without affecting the dynamics of hard-panned tracks. Or add Ozone's mastering reverb to the side channel to soak hard-panned guitars in a wash of ambience while leaving tracks in the center untouched. You can toggle Ozone's I/O meters to read either stereo or M-S levels.

Master controls allow you to increase or decrease the overall amount of processing independently for each module and for the entire plug-in. You can also bypass individual modules and change their order in the signal chain. More than 370 parameters in Ozone can be automated (assuming your digital audio sequencer supports effects automation).

Drilling Deeper

Ozone's Paragraphic Equalizer module lets you mix and match eight bands of bell-curve, highpass, lowpass, and high- and low-shelving filters (see Fig. 1). Choose either linear digital filters or analog-modeled ones that emulate vintage tube gear. Adjust the frequency, gain, and Q (bandwidth) of each band to taste. You can also capture the frequency spectrum of a favorite mix and make your current mix mirror that response.

Ozone's Mastering Reverb module offers both plate and room reverbs. You can control the reverb's size (tail decay), pre-delay, width, high-frequency damping, bandwidth, and wet/dry mix.

The Multiband Harmonic Exciter module can be set to emulate transistor, tape, or tube saturation. A new, fourth saturation mode generates only quickly decaying even harmonics. You can separately adjust the amount of harmonics and the wet/dry mix for each band. You can also delay each band by separate amounts to compensate for group delay; for example, delaying the low-frequency band slightly can make a flabby kick drum sound tighter.

A separate compressor, limiter, and expander in each band of the Multiband Dynamics module have their own threshold, ratio, attack, and release controls (see Fig. 2). The expander can produce either upward or downward expansion. You can defeat the module's automatic makeup gain and choose either RMS or peak detection for the common sidechain. You can also adjust the balance of processed and unprocessed sound in each band to create parallel compression effects, thereby preserving transients.