Review: iZotope Iris 2

Software instrument and sound-design tool with improved workflow
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Iris is a sample-playback synth with a difference—in fact, with many differences that keep it at the top of my list for twisted and breathtaking sound design. And with version 2, iZotope has upped the ante considerably.

Iris 2 shares some operational concepts with U&I Metasynth’s Image Filter and Spectral Synth. Central to Iris 2 is the ability to bring WAV and AIF samples into the oscillators (or sample pools, in iZotope terminology), which then produces a spectrographic image. Using a varied set of tools not unlike a graphics editor, you can freely draw filters along the time and frequency domains, creating sounds with timbral motion ranging from minute and subtle to huge and drastic.

Iris operates as a standalone instrument as well as AU, RTAS, VST, VST3, and AAX plug-in instruments. An enhanced sample library, new to version 2, is nicely laid out, with nearly 11 GB of 24- bit samples, ranging in category from synths and granulated sounds to toys and household objects.


Fig. 2. Clicking on the Iris Patch window lets you select patches, exchange samples, and tweak new patches while you audition sounds.At first glance, the synth’s single-page user interface seems a bit busy, but in reality, everything is organized into a quick, easy-to-understand workflow, with many of the deeper features conveniently tucked away. The header area—consistent no matter what your editing task—deals with global and performance parameters, as well as patch-management chores. Resize the window to suit your visual comfort.

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If you are accustomed to working with the original Iris interface, you can hide the new modulation, keyboard, and master sections by clicking on small triangles to focus on the Spectral Modulation window, which remains relatively unchanged from version 1. The patch window, however, is emblematic of the new GUI design: One click brings up a set of tabs that let you choose patches, but they also access the Iris sample pool and the Osc Waves section, which contains a collection of analog synth waveforms (see Figure 2). Move from one oscillator to the next and choose your own samples, or select a new patch. It’s useful to have these functions under one menu and it’s a tremendous aid in designing your own sounds, allowing you to use pre-existing patch settings as a starting point.

Eight assignable macro knobs allow you to adjust your choice of parameters such as envelope and effects settings. It’s a great way to tweak a sound without leaving the auditioning environment. If this is more than you need, just click the Simple Browser button on the Patch window’s lower left to constrain the view to patch categories and their macros.

By the way, if you already own version 1, an import window lets you bring legacy patches into the new version, and an export button bundles the samples with the patch, letting you share patches with others. Some features, such as the Manage Libraries button, offer redundant access to other menus, which in this case is fine, as it contributes to the workflow without making the redundancies intrusive.

The revamped Iris modulation section is a pleasure to use: Drag and drop modulation sources to any destination without limit; modulate LFOs with LFOs (see Figure 3). Color coding for each modulation type makes it easy to see the routing, abetted by a numeral for each modulator. For instance, a yellow circle with a 3 on the destination will tell you that the modulation source is LFO 3 of the five LFOs. Likewise, you get five Envelope Generators, the fifth of which is hard-wired to the Master Output but is also freely assignable to other destinations.


As you may know, the Iris Spectral filter window derives from iZotope RX, the company’s remarkable audio-repair plug-in. The window is informative and appealing, letting you crossfade between spectral and waveform overviews. The selection tools appear on the left, abutting the frequency plot. It can be difficult to translate the graphics into precisely predictable results, but unlimited undo offers encouragement for experimentation. And the great-sounding selection of effects, filters, and extensive modulation capabilities can be used to greatly enhance the fruits of your labor.

As with the Spectral Filter, iZotope has cross-collateralized the distortion-modeling DSP from its Trash plug-in. Choose from a half-dozen distortion types, including Saturation, Tube distortion, Clipping and Asymmetrical. I like being able to compound the distortion that occurs at higher gain with velocity or ride it with a mod wheel.

The Master filter sounds great. Lowpass, bandpass, highpass, and peak filters offer submenus with variations on each theme. The programming interface for effects can be tucked away.


It’s impossible to describe what Iris sounds like: transparent and sparkly on one patch; rude, glitchy, and spitting sparks on another; thick and analog-sounding on the next. Because you can load your own WAV and AIF files, the sky is the limit as to where you can take this program.

The Spectral Filter can drastically alter the sound of anything you throw at it. You can make tonal sounds atonal, or emphasize fundamental frequencies in sounds that have no clear pitch and turn them into tonal instruments. Iris is as much a sound designer’s tool as it is a musical instrument.

For all that, the star of the show in version 2 is the redesigned workflow. Navigating and programming Iris 2 is palpably streamlined compared with Version 1; Iris fans will definitely want to upgrade. Sound designers and musicians in search of exotic-sounding synthesis should download the demo program and check it out.


Streamlined and intuitive workflow. Feature-rich synth. Intuitive and flexible modulation system. Generous and intriguing sound library.


Nothing significant.