Review: iZotope VocalSynth

A plug-in suite of effects for modern productions
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IZotope’s slogan for its VocalSynth plug-in is “Think Outside The Vox.” But while it is easy to see through such marketing hype, this is an instance of the manufacturer absolutely nailing it. The premise of the plug-in is straightforward: Collect the most popular vocal processing tools for modern electronic music into a single software program that allows you to combine them quickly and seamlessly in innovative ways.

iZotope VocalSynth combines four popular vocal-processing tools in one simple interface. Of course, you may already have a few or all of these types of tools at your disposal, thanks to the now-standard inclusion of vocoders and pitch correction in most modern DAWs. However, by putting them all in one plug-in, VocalSynth provides a streamlined workflow that won’t get in the way of creativity.

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VocalSynth’s interface is wonderfully direct, with four discrete vocal-specific effects—Polyvox, Vocoder, Compuvox, and Talkbox—accessible simultaneously, as well as five additional effects that further distort and mangle audio in creative ways. The software also includes an adjustable pitch-correction processor on the input, along with an x/y controller that gives you real-time access to two simultaneous parameters for creating flashy performance tricks. Finally, there’s an FFT-like effects display that is reminiscent of Native Instruments’ Razor.

VocalSynth’s pitch-correction tools are direct and to the point, offering parameters for key and major/minor/chromatic scale, as well as the ability to create custom scales using a simple one-octave keyboard icon. There are also controls for adjusting the strength and speed of pitch correction.

While the absence of additional scales and modes may be a disappointment for some, VocalSynth is positioned squarely at the pop, dance, and hip-hop markets, so these limitations may indeed speed up production decisions. And those with more exotic scale requirements can always use the custom keyboard.

Now let’s look at each of the effects categories individually to see what they offer.



If you’re a fan of Imogen Heap’s legendary track “Hide and Seek,” Polyvox will have you smiling. While many have mistaken the original effect for a vocoder, it is actually much closer to DigiTech’s vintage Vocalist effect (or TC Helicon’s Voice Pro, as a more modern example). Essentially, it’s a polyphonic pitch shifter with controls for Formant, Character, and Humanize.

Formant allows you to shift the vocal tone down toward Darth Vader or upward toward the Chipmunks; by leaving the value centered, you get a more natural sound. Character modifies the formant shifting to reflect the original performance’s behavior. Humanize adds a bit of randomized “chaos” to the final output—a small amount imparts a more natural effect while higher settings increase dissonance in the layered harmonies.

As for setting up the chord voicings, VocalSynth offers two methods: You can use MIDI control or set up three discrete intervals via the center panel of the interface. For example, if your goal is to create traditional seventh-chord harmonies, just set these controls to third, fifth, and seventh and let the software do the work. For more specific progressions, switch to MIDI control and play your chords and melodies.



Compared to the vocoders that ship with most of the current DAWs, VocalSynth’s customization options are decidedly minimal—four parameters and options for ten different preset oscillator types for the integrated synthesizer (carrier). These oscillators are modeled after famous vocoder-based tracks. With names like “Planet Galaxy” and “Classic Bahns” it’s pretty easy to figure out the inspiration for each type, which helps if you already know what sound you’re targeting.

The four parameters are Mode, Shift, Contour, and Scale. The Mode selector switches between Smooth, Vintage, and Hard behaviors, each of which offers flavors that seem to correlate with the number of vocoder bands and their sensitivity (though this is an educated guess, because the manual doesn’t include any information about it). For most applications, the Vintage mode is what you’re looking for, though the modern sound of the Hard mode may be better suited to current styles of EDM. I was a tiny bit surprised that there wasn’t a fourth mode dedicated to extremely narrow vocoder bands, as that approach results in the ethereal and metallic textures popularized by Sasha’s productions and still sounds quite futuristic by today’s standards.

Of the other three parameters, Shift is used to adjust the vocoder’s apparent formant characteristics, while Contour and Scale modify the emphasis of various bands and the response time of the vocoder. Ultimately, this particular vocoder is laser-focused on whipping up familiar sounds with a minimum of fiddling, and for producers who are intimidated by the intricacies of full-featured vocoding tools, this alone could be a huge bonus.



Ostensibly a simulation of Linear Predictive Encoding—the technology behind the speech synthesis in toys such as the Speak & Spell and ’70s-era talking calculators—Compuvox ultimately sounds like a noise-based vocoder with integrated bitcrushing, which frankly isn’t a bad way to simulate these vocal effects. That said, there is clearly a bit more going on under the hood. While the parameters alone aren’t quite enough to turn your voice into the friendly authoritarian that seemed to inhabit those early devices, your own intonation and ability to ham it up should make up the difference.

Once you’ve got the right delivery tracked, Compuvox’s parameters are great for precisely sculpting the sound into a credible facsimile of the LPC approach. Like the vocoder, it offers ten oscillator types, each based on a different digital waveform, with an emphasis on noise carriers, though there are a few pitched options. From there, the results are further customized via four knobs. Bits, aptly, adds bit-crushing to the process. Bytes imparts a really cool sample-and-hold granular process to the effect that absolutely nails Kraftwerk’s “Computer World” vocal stylizations and gives Compuvox its own unique flavor. (Forward-thinking producers are going to love that parameter.) The Bats knob adds a gravelly texture that the manual strongly implies is based on Batman’s voice, but ultimately is simply another useful way to customize the sound. Lastly, the Spell switch offers three EQ-like curves to the digital/noise element of the sound.


A real talkbox consists of a speaker connected to a tube that’s placed in the performer’s mouth, which is then used as an artificial voice box, where the oral cavity serves as a complex resonator and the tongue provides articulation for consonant and vowel sounds. Despite its apparent simplicity, the nuances of the talkbox effect are incredibly difficult to reproduce convincingly by any other means. That said, iZotope has done a great job of replicating the essential character by what appears to be a fusion of the Polyvox technology and its Vocoder algorithms. Here, the customization parameters include the now-familiar oscillator type and formant controls, along with knobs for overdrive, speaker emulation, and a Bright selector offering different frequency responses.



While the vocal effects described above operate in parallel and include individual level controls in a central mixer, five additional effects at the end of the chain do a great job of both consolidating the sound and ratcheting up its electronic aspects.

These effects include Distort (a waveshaper/overdrive), Filter (great for French House flourishes), Transform (a convolution-based speaker emulation), Delay, and a new effect called Shred that fuses bits of iZotope’s Stutter Edit technology with granular-synthesis effects. I particularly dug the way Shred enhanced the output of the Compuvox effect, as it further “computerizes” its character.

Moreover, VocalSynth offers both polyphonic MIDI control of its synth elements and sidechain options for swapping out its carriers with your own audio, which is a fantastic way to combine its vocal effects with other recorded tracks in your compositions. While each DAW’s approach to routing MIDI and audio to plug-ins is unique, I had no trouble routing either type of data within Ableton Live.



VocalSynth’s blend of classic vocal processing tools with intuitive and simplified parameters puts its focus squarely on getting great results with a minimum of fuss. What’s more, the additional effects, comprehensive DAW integration, and impressive collection of presets make it useful for far more than just pop vocal stylings. VocalSynth’s unique sound has inspiration baked right in, and for some producers of electronic music, that’s worth any price.

VocalSynth Effects

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While the main focus of VocalSynth is its array of vocoder-oriented tools, its effects section is remarkably useful for processing instrumentation and audio of all shapes and sizes. The signal chain is preconfigured in a serial manner—distortion followed by filter, speaker emulation, a stuttering/granular tool, and a delay—so other than turning effects on or off, you can’t rearrange their positions, but iZotope clearly designed this chain for maximum flexibility.

The distortion, filter, and speaker emulations all offer several different algorithms, so they can go from subtle warming effects to full-on signal mangling. In a way, it’s like having a lite version of iZotope’s indispensible Trash 2 plug-in baked right into VocalSynth, which is impressive indeed. These three effects alone are great for everything from distorted guitars to industrial drum loops. The stutter/granular tool, called “Shred,” is useful for both static flanges and exotic chopped effects. And the delay at the end of the chain, while basic, is still handy because its settings can be saved as part of any given preset.

The end result is that VocalSynth also gives you a solid set of traditional processing tools with the “iZotope sound” for manipulating non-vocal material, adding a lot of value to the package. In fact, it’s not a huge stretch to say that VocalSynth is actually two products that cover different territories and can be used either individually or together for some truly unusual tonal sculpting.


Four unique and popular vocal effects. Streamlined and immediately accessible parameters. Five additional effects. MIDI and sidechain tools for real-time playability. Impressive presets.

x/y interface only allows for one parameter per axis. Vocoder parameters are a bit limited in scope. No standalone version.


Producer Francis Preve has been designing synthesizer presets professionally since 2000. You can check out his new soundware company at