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iZotope Ozone 3 Analog Mastering System

Ozone 3 is the fullest-featured, highest quality DAW mastering — at an unbeatable price

Even though I had never personally used it, two of my music-making buddies purchased Ozone — iZotope’s inexpensive do-it-all mastering suite — on my recommendation, which was based on both what I had heard about it and its low price. I reasoned Ozone’s powerful presets would quickly carve their creations into convincing masters. Dan Comerford of the San Diego band Lucy’s Fur Coat has been sending me mastered versions of his demos ever since, reporting on his explorations into the intricacies of Ozone along the way. I never pictured using it myself, as an under-$200-street plug-in “couldn’t possibly be as professional as the tools I was already using.” But iZotope, I misjudged you. I found that just as ozone in the upper atmosphere filters out potentially damaging ultraviolet light, iZotope’s Ozone, when used properly, can rescue our ears from potentially uninteresting sound.

Ozone 3 Dynamics How can a computer plug-in be called an “analog mastering system?” The EQ has an analog mode and the multiband harmonic exciter section offers tape, tube, and “retro” emulations. I’m excited that all processing is done in the 64-bit domain and buoyed by iZotope’s claim that artifact problems associated with chaining together separate plug-ins are eliminated. I believe this is due to two factors: 1.) Ozone’s three multiband modules use the same crossover network and settings, and 2.) Once the signal is converted to 64-bit, it does not have to be re-dithered until the final output.


Ozone is divided into 6 processing modules: EQ, reverb, multiband dynamics, exciter, and imaging, and loudness maximizer. Menus allow for adjustment of sonic parameters, metering, and other behaviors. The Graph menu gives access to signal chain order as if each module were a separate plug-in.

Ozone’s GUI usurps some of the computer keyboard’s function keys. F5, which is regularly used to engage the zoom tool in Pro Tools, became the accidental bane of my existence as it resets the current module. One hundred levels of undo within the plug-in more than made up for the annoyance. F1 takes one directly to online help.

On initial instance, Ozone’s extensive preset menu appears. I typically have a specific task in mind when I reach for a plug-in, so I’m not likely to first try a preset. Yet the manufacturer’s presets can educate as to how the designers intend one get the most out of the software. To start with a blank screen, uncheck the box “Show at Startup” under the preset menu.

Modeled after mastering grade, valve-type analog equalization, Ozone’s analog EQ mode offers a gorgeous sound, while linear phase digital EQ offers transparency. This is amongst the finest plug-in EQs I’ve heard.

The equalizer encourages broad strokes, but learning the modifier keys is a must for micro adjustments. Filter types and values for the eight bands can be entered manually via the “Show Info” menu.

The EQ snapshot menu stores favorite settings and target and source curves for the outstanding EQ matching function. In the past I’d resisted this copycat trick on some stubborn principal. Ozone presented me with my first opportunity to check it out.

Ozone 3 Equalizer In Use

The first step is to find a track embodying the spectral target you want to hit. The target material chosen will have the greatest effect on the outcome. More than 8000 linear phase EQ frequency bands are available to match source to target spectrum. For my test, I selected three very different pop/rock songs.

Number one was an un-mastered Just Jinjer song I had mixed a couple years ago. The Dandy Warhols tune I referenced during my mix seemed the ideal EQ target candidate, but the tone of the verses and choruses were so different between the songs, EQ matching didn’t sound right. A solution could be to match verses separately from choruses.

My second source was a Kid Dakota track I had previously mastered to retain dynamics. I loaded a favorite Green Day track as a target just to see what would happen. With EQ matching and some additional limiting, I could easily match my master to the major label release.

Finally, my attempt to match my Mudvayne mix to an American Head Charge mix produced a comb filtering sound in the high frequencies at the most aggressive matching percentage. The “smoothing” slider cleared up the problem, but made the low end matching less accurate. I’d suggest iZotope separate low, mid, and high controls for the smoothing parameter.

EQ matching works so great that I wish there were a dynamics-matching feature, too. In any case, just turn up the limiter four to six dB more than you think sounds good, and you will have a commercially competitive master! (I’m kidding, please don’t.) Clicking Alt-Solo on a frequency band brings up Ozone’s zooming feature previously available to me only in the astutely designed Massenburg DesignWorks Hi-Res EQ.

The quality of the crossover will have the greatest effect on a multiband processor’s sound. Whether in analog or linear phase digital mode, Ozone’s crossovers sound great. Due to the extreme power of multiband compression, limiting, gating, and upward expansion, this module can shine up — or when used improperly, destroy — a master.

I especially liked Ozone’s auto attack and release settings, but my favorite tool for subtly improving a great mix is the expander. For one song on The Get Up Johns record, I employed the high frequency section of the multiband dynamics to expand high frequencies above 3.5kHz by a ratio of 1:1.1 below a threshold of –29.6dB, effectively reaching down into the mix to reveal low-level treble information. It can increase the HF noise floor slightly, but by automating the ratio from a negative number (upward expansion) to a positive number (downward expansion), the dynamics control works like a noise reduction circuit. Unfortunately, the traditional method of holding Control Option Command and clicking on a plug-in parameter will not enable that parameter for automation as is the standard method within Pro Tools. I wish also there were a way to change any parameter simultaneously within all bands, but one can copy and paste settings between bands.

Without fail, A/B-ing with vs. without, the harmonic exciter would win every time. The ability to determine the intensity and mix of tape, tube, and the crunchy “retro” per each of four bands is pure genius. Be careful, though — loads of harmonic distortion can sound pleasing at first, but might not translate well over time or on other systems; I found out while transforming an excellent all-digital (the piano instrument was Ivory software instrument) classical piano recording by LA producer/composer Wayne Jones from clear and clean to something slightly older and more sonically soulful. It took me back to hearing classical piano recordings from the 1960s. On another of Wayne’s records, headphones revealed my tube harmonics settings — while great on the vocal, bass and guitars — were turning the piano into a box of crunchy Cracker Jack. Dialing back the drive amount and mix controls fixed it. In a future Ozone release, I’d like to see a master control to move all bands at once and the facility to set different types of distortion per band.

The icing on this module’s cake is its ability to put the low frequencies slightly ahead of the highs to increase perceived punch of the low end. There are two reasons this can be effective: 1.) Low frequencies are slower and take longer to get to us. Advancing the lows just a millisecond can line them up acoustically in your room, and 2.) The loudness maximizer won’t have to work as hard if it doesn’t have to limit the energy-heavy lows at precisely the same time as the rest of the spectral content. Fast Facts Applications
Studio, project studio, mastering, audio for broadcast

6 processing modules for audio mastering: EQ, reverb, multiband dynamics, exciter, and imaging, and loudness maximizer.

$249 list

isotope | 617-577-7799 |

Ozone’s imager goes to another level by offering band-specific image control; for instance, one might want to make the low frequencies mono to increase punch, then expand the width of the midrange to push the guitars wider. A phase correlation meter is integral to the module.

Ozone offers plate and room type reverbs that can be blended with the dry signal at any ratio. In small amounts, these short RT60 verbs can add depth to overly dry masters.

Whenever faced with the dilemma of CPU performance vs. sound quality, iZotope claims to have favored sound quality. At 44.1k, I could run 12 instances of Ozone in Pro Tools with all modules engaged before my CPU overloaded. Why, that’s enough to master a whole record! Under all conditions, the GUI loads painfully slowly (about 4 seconds), partly due to their intense graphics displays. Not just pretty light shows, Ozone contains a comprehensive suite of informative, user adjustable metering. To help relieve the processor strain, clever iZotope allows toggling of all meters.

Great for the user-manual averse, one click of the question mark icon launches online help for that module via web browser. iZotope’s website guided me through several features, such as EQ matching, that I didn’t previously know how to use. Over my first three days mastering with the plug-in I kept myself enrolled in Ozone Online Community College.


Ozone is complex, but well worth the learning curve. Now, after getting to know it myself, I feel guilty for having unwittingly exposed my musician buddies to such an elaborate feature set. No doubt through their continued use of Ozone they got a thorough education into nearly all that is possible in spectral and dynamics manipulation. I auditioned this plug-in exclusively in a mastering role, but its powerful features could certainly produce stunning and creative results on individual tracks or subgroups.

A must have for DAW-based mastering engineers, iZotope’s Ozone 3 is the most powerful (enough to get into a lot of trouble), fully-featured mastering plug-in I’ve used, with sound quality equal to or better than any other. The EQ sounds smooth and analog rich, the crossovers are musical and transparent, the harmonic exciter tone-elevating, the multiband dynamics capable of magic tricks, and the loudness maximizer state of the art. Even the M-Bit dither says, “Come hither.”

Alex Oana is an award wining engineer, who mixes and masters at his studio in Los Angeles.