Electro-Harmonix Voice Box Quick Pick Review

Electro-Harmonix Voice Box Vocoder and Harmony Processor reviewed by EM author David Battino in EM August 2009 issue
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The rugged Voice Box is a vocoder and harmony processor with a strong personality, simple yet flexible controls and a friendly price.

As soon as I saw Jack Conte's astonishing online demo (see Web Clip 1), I knew I had to check out the Voice Box. It looks like a guitar pedal, but it contains one of the best vocoders I've heard, along with a vocal harmony generator, a wonderful whistle effect and more surprises. And as Conte ably demonstrates, you can drive it with everything from guitar to keyboards. I've been controlling mine with iPhone synths for extra portability.

The Voice Box takes two inputs — microphone and instrument — and combines them in various ways. In Harmony modes (there are six variations), the box detects the note or chord your instrument is playing and uses that data to generate harmonies for the mic signal. In Vocoder mode, the instrument input determines pitch and basic timbre, and the mic input makes the instrument “speak.” Octave and Whistle modes ignore the instrument input, processing just the mic input. You can store one set of knob settings per mode and recall them with a tap of your foot.


The Voice Box feels solid. It's built into a beefy aluminum case, with knobs, jacks and heavy-duty switches bolted on. The only weak points I spotted were the generic wallwart adapter (alas, battery power is not supported) and an unprotected switch on the right side that toggles phantom power for the XLR mic input.

The right side also holds the ¼-inch, unbalanced mono input for guitar or line-level signals. On the left are the effects output (a balanced XLR) and a ¼-inch pass-through jack for the instrument input. That lets you daisy-chain the Voice Box to a guitar amp or additional effects boxes. Electro-Harmonix says the XLR output interfaces better with mixers and breakout boxes. I think a combo XLR/¼-inch jack would have been more convenient, even if it cost more, because I often wanted to route the Voice Box into another effect.

The white knob on the top-right scrolls through nine effects modes: Low Harmony, High Harmony, Low+High Harmony, Multi-Harmony 1/2/3, Octaves, Unison+Whistle and Vocoder. Holding the knob down stores the positions of the other five knobs for that mode. Pressing down on the white knob loads the stored preset for the current effect. You can also cycle through the nine presets by stomping on the Preset footswitch on the bottom-right. It's an elegant system. The other footswitch, marked Mic Bypass, is actually an effects bypass, which initially confused me, but the concise manual explains everything clearly.

The remaining knobs control the mix of mic and effect; the amounts of reverb on the mic and effect signals; a formant shift (aka, Gender Bender); and the balance of harmony voices. In Unison+Whistle mode, this last knob pans between a formant-doubling effect and a whistle tone derived from the mic input. In Vocoder mode, the knob brightens the instrument signal to increase intelligibility.


The 256-band vocoder sounded both rich and intelligible, even when I drove it from a $15 dynamic mic. Unlike other vocoders, it has no confusing filter parameters; you just plug in and start sounding great. That said, you can alter the sound dramatically by changing the timbre you send to the instrument input. Buzzy sawtooth chords work well for classic vocoder effects, but I got some fascinating sounds by feeding the Voice Box some burbling textures from a PCM synth (see Web Clip 2).

I was less successful with the harmony effects, which generate a mixture of (mostly) thirds, fifths and octaves based on the mode and the input signal. With no pitch correction, these effects really depend on rock-solid singing to produce a pleasing output. The voices also sounded, well, furry, like a thickening effect rather than an additional singer (see Web Clip 3). I also had a lot of fun with the Whistle effect, which synthesizes a whistling tone two octaves up from the mic signal (see Web Clip 4).


At $215 street, the Voice Box would be an excellent value just for the vocoder, which sounds excellent and is easy to use. It's remarkably intelligible while still sounding lush. The harmony effects are harder to control and don't sound as natural as the competition, but can add richness if used subtly. Similarly, the murky built-in mono reverb didn't do much for me; I'd have preferred a delay with tap-tempo. Having just one preset per effect may seem limiting, but you can change the vocoder sound dramatically by selecting different input timbres. If you're looking to add expression or fullness to your sound, the Voice Box would like to speak with you.

Overall rating (1 through 5): 4