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iZotope Iris Spectral Synth Review

Published: Tuesday 31 July 2012

If music plug-ins were a college class, iZotope would be the kid you know is going to ace all of their exams while still somehow finding the time to be effortlessly cool. Iris, then, is the sonic equivalent of that kid’s pair of aviator sunglasses.

iZotope Iris

Yes, Iris has landed, and manages the tricky double-up of looking beautiful in its creativity while providing sounds that not only are immediately and dynamically useable in your arrangement and songwriting, but are also utterly unique to you. This of course comes with something of a learning curve, so let’s take a look at what Iris actually is and does.

Let’s get spectral

It’s a synth that uses spectral imaging as an instrument. You’ll have seen the technology before in RX, which allowed you to visually apply restorative editing to audio tracks, but this time around, this VST(3)/AU/RTAS and standalone software has been created as a ‘sampling resynthesiser’.

What? Well. Drop a sound into Iris and it’s displayed in a spectral pattern that glows brighter at different points. This brightness represents the amplitude of the sound – more level is brighter, obviously – while the X/Y axes of the panel the imaging resides within represent time and frequency respectively. So you’re working across the timeline of your sample and as the image climbs higher in the box you’re moving up towards higher pitches. So far, so simple.

I’ve dropped in a sample, in my particular first-review case a vocal take I recorded a while back. And there it is, all resplendent spectrally. It’s resampled to my keyboard, either time/pitch stretched so that pitch doesn’t affect sample length or more simply speeding it up for higher incarnations of the sample, slowing it for lower. You can choose which, and in this case I’ve opted for the former.

It’s worth noting that if you don’t want to use your own samples there are 4GB worth included that give you a significant starter for 10. This is no bad thing as playing with your own ideas is brilliant but if you want to hone in on specific synth piano or pad sounds for instance you might find that layering the preset material can yield faster successes until you really know the software, and will be no less unique.

Thing is, I don’t want to use all of my sample, just a specific part of my vocal, as the core of my sound. There are tons of editing tools to make this possible, and to take things much, much deeper too.

Tool time

So I can use ‘deselection’ to rub out bits I don’t want. I can narrow down frequencies to focus entirely on the high end, or I can use a selection tool to poach only small parts of an overall spectral image. This is particularly useful if you’re using a sample with multiple tonalities and you’d rather use only a specific part, rub out the rest and keep what you want intact.

iZotope Iris Screen Grab

The tools sound complex but are actually easy as anything to apply, having as much in common with Photoshop drawing tools as with anything in the audio world. This is particularly evident with the magic wand tool, which is a gem. It analyses the harmonics of whatever you’ve highlighted and finds other areas within the sample that have a relatively similar makeup. Brilliant, especially for more precise isolation.

What it means is that there’s a lot of mileage in just about anything. Any sample has possibilities and often not the ones you’d expect. You’re encouraged to play!

Layer up

You can then layer your sounds – three per patch plus a sub – and mix these to create an overall soundscape that draws on the various strengths of each sample and either makes for fractious, darting-about articulative patterns or thick and even monstrous expansions.

Mixing is an easy affair and you’re able to bring more traditional synthesis efforts into proceedings at this point – assignable LFOs, envelopes, effects (distortion, chorus, delay and reverb for send or insert applications).

iZotope Iris Box

The sub layer we mentioned felt like an imposition until it became evident that this is the glue that holds your samples together. The theory being that blending three samples together to create your patch might produce something clever, but not necessarily entirely useable when it comes to a consistent and cohesive idea. The sub thickens that out via the selection of various waveforms that enrich the lower frequencies, giving you a foundation to wax lyrical over. Spectral imaging and editing is once again possible here, but in some ways it would be a little dangerous to start creating gaps in this – it really is there for a reason, and especially those of you heading into pop and hip-hop realms will find the familiarity of those sub patterns a real comfort. For more experimental work you don’t need to include the sub of course.

For further familiarity, the envelope options can create very specific analogue emulations, so if you need to bring in your sample fiddling to a particular sound for context, you very much can.


I love Iris a great deal. It doesn’t ask a lot of you once you understand how it’s working in its simplest form, and the editing tools are neat and precise while encouraging experimentation.

For the user who can never get the sound they’re after just-so, here’s your solution. I’ve even found myself creating samples specifically so I can them layer them into Iris! It’s a great synth that will open up a new world of sound creation to any producer or engineer with enough aptitude and processing power.

Reviewed by Rob Sandall

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