Izotope Iris

November 21, 2012
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by FRANCIS PREVE

Izotope Iris synth editing screen
Familiar synth staples like a filter, envelopes, and effects are on hand as well.
ONCE UPON A TIME (OKAY, IT WAS 1998), A SMALL COMPANY NAMED
U&I Software created a revolutionary virtual instrument called MetaSynth. Saying that MetaSynth was ahead of its time is a little like saying that Nikola Tesla had some forward-thinking ideas. Any sound, however complex, can be thought of as a stack of sine waves at different frequencies and volumes. MetaSynth—which is still in production—could resynthesize any sound into a visually editable Fourier transform of this stack, which gave sound designers the ability to manipulate audio at what felt like the Higgs boson level. The problem with it was that these processes were neither truly realtime nor available as a playable plug-in instrument. So when iZotope recently announced Iris—a realtime plug-in soft synth that delivers some of MetaSynth’s power, but with an even more approachable interface— additive resynthesis cultists rejoiced.

How It Works
The essential principles of Iris are immediately intuitive. When an audio file is imported into Iris’ sampler-like environment, its frequencies are analyzed and displayed visually as a graphic pattern, with the vertical axis representing pitch, the horizontal axis representing time, and the brightness of the multicolored pattern components representing the volume of each frequency. From there, you can process and affect the sound by painting on the graphic, thus highlighting or exposing specific regions of the sound’s visual representation.

For example, using the paintbrush tool, you can highlight certain harmonic components of a sample, making them audible. Paint at the bottom and you’ll hear the lower frequencies. Draw at the top of the image and you’ll hear the high- frequency components. Paint a wide swath from the upper left corner to the lower right, and the result is reminiscent of a lowpass or bandpass filter envelope decaying over time. That’s just the easy stuff. There’s also a “magic wand” tool that selects contiguous areas of the image, based on their brightness and proximity to each other. Other tools include rectangular selectors for ex- posing “blocks” of audio, and of course, an erase tool for refining your audio selections.

In practice, Iris functions as a three-layer sampler, with an extra “sub” layer that offers preset selections for classic synth waveforms like sine, saw, square, pulse, and a few noise options. As with the samples, you can use the painting tools to refine frequencies in truly unique ways, delivering exotic animation that would be nearly impossible to achieve via filters and LFOs alone.

While each of Iris’ audio layers function similarly to a sampler, there’s no true multisampling, so what you get is the same audio source mapped across the entire keyboard range. Granted, you can split the key ranges for each of the three layers to get an approximation of multiple key zones. That said, this isn’t really a drawback, since Iris’ forte is abstract soundscapes that you can’t achieve using other synth tools.

Even so, Iris does have some nifty sampling tricks up its sleeve, like a choice between straight resampling and iZotope’s Radius RT time-stretching algorithm, which preserves the timing of the original sample while the keyboard changes the pitch as you play. There’s also a fixed mode that makes the sample play back at a specified pitch regardless of what key you play.

As for traditional synthesis tools, Iris is loaded with all of the essentials. Each layer has its own ADSR envelope and a multi-wave LFO that can be assigned to pitch, volume, or pan. Of course, there’s also individual volume and panning to fi ne-tune the mix of elements.

Globally, there’s a multimode filter, which is applied to all four layers as a whole. iZotope didn’t skimp here either, offering vintage filter modes for each, including a nice TB-303 model and a few saturated and screaming bandpass options.

Rounding out the whole package, Iris includes an array of four simultaneous effects—distortion, chorus, delay and reverb—which can be applied to the master outs or used as individual sends on each layer. All effects are quality implementations, but the distortion is especially flexible, with six different types ranging from a warm tube emulation to nasty saturation.

A macro section lets you control multiple, linked parameters from up to eight knobs a la Ableton Live, and there’s also an X/Y pad. While there’s a selection of presets that do clever tricks, you can create your own assignments by right- clicking on desired parameters. This is incredible for crazy morphing effects and automation sleight-of-hand.

In Use
Iris comes with a 4GB sample library to get you up and running, and the majority of the material really demonstrates the power of this synth. There are also two a la carte libraries of samples derived from glass and wood Foley-style recordings like marbles, smashes, door slams, and firewood—all transformed into ethereal, sometimes eerie, sometimes majestic soundscapes. A package including the glass and wood libraries plus Iris itself adds $50 to the overall price.

With a synth this intuitive, the real fun comes from rolling your own material, either by running around with a microphone or dusting off a musty old sample library and breathing new life into it. Since, as mentioned, sound itself is based on multiple sine waves, you can drop literally anything into an Iris layer, let the synth commence its resampling magic—which includes detecting the inherent key of the material—and then paint the audio into something truly unique. Even a single layer can leave your listeners wondering, “How the heck was that sound created?”

When you start layering two or more samples and maybe folding in a classic wave for support, Iris truly comes to life. To demonstrate how in- sanely powerful Iris can be, I created two audio examples for this review. The first one is based on a loop of me saying “Keyboard magazine” that morphs into a powerful electro/dubstep bass line and then a glistening soundscape. The growling bass effect is derived by shaving off the high frequencies with an undulating painting, which was then processed further using Iris’ distortion.

The second example is derived from a short Foley sample of a ship at sea that morphs into an ethereal ambience that really must be heard to be appreciated. I began by painting the lower frequencies first, then adding an upper frequency sweep. From there I added a paint-processed square wave, then some filtering, then stereo delay and reverb. Each step of the morphing process is clearly audible.

As with any 1.0 release, I encountered a few unrepeatable glitches, including a moment where the UI stopped responding and needed a reboot (I’d been saving as I went along, so I recovered my work quickly). For the most part, though, Iris was quite stable and totally fluid.

Additionally, the MetaSynth lover in me was yearning for two wish list features: the ability to import image files into the resynthesis engine (for recreating classic Aphex Twin-style effects) and a broader array of image editing tools, but give me a yard and I’ll beg for a mile—Iris is still the most intuitive and unique synth for this type of Fourier work, by far.

Conclusions
When it comes to soft synths, I’ve used them all, and the only ones that make it into my daily workflow are those that deliver results that I simply can’t get from my analog and modular gear. Ableton Operator and Collision, Native Instruments Komplete, and Korg’s Digital Legacy collection are mainstays. What can I say? I like synths with personality, which Iris has for days.

In fact, the first night I used Iris, I created the foundation for an ethereal, melancholy progressive track. Iris is pure inspiration from the moment you drop it into a track. If you’re a synthesist who’s constantly prowling for revolutionary methods of sound design and who makes a point of avoiding me-too patches, then Iris will deliver mind-melting results. For $249, this kind of innovation is clearly a Key Buy.

Snap Judgment
PROS Additive Fourier resynthesis with a graphic interface anyone can understand. Collection of unique and powerful filters. Quality effects. Macro options that make realtime morphing easy to automate.

CONS Somewhat CPU- intensive when using Radius RT time-stretching resampling.

Bottom Line
An amazing new treasure chest of sonic possibilities that you can manipulate with graphical, painting-like gestures.

$249 list | $199 street izotope.com

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