Review: Electro-Harmonix Mono Synth

This new sonic mind-bender offers plenty of potential power. Just remember to play one note at a time!

Review Overview

Our rating


Our verdict

A monophonic guitar synth with a lot of potential power. Just remember to play one note at a time!

Never ones to shy from the road less travelled, EHX released the Attack Decay Tape Reverse Simulator and Mono Synth at Winter NAMM in January 2019. Our primary concerns when unleashing this kind of equipment have to be whether it gets weird enough for our tastes, whether it offers the sort of control that keeps things creative, whether you will have any money left afterwards and if not, how much you’ll care.

The new Mono Synth is a monophonic synthesiser with no fewer than 11 different synth voices to explore. It also offers preset storage and expression-pedal connectivity.

Guitars and synthesisers have had an uneasy relationship and it is only relatively recently that convincing synth sounds have been accessible without resorting to a MIDI pickup. Dutifully following EHX’s recommendation, we put the Mono Synth at the start of our chain and go straight in.

Tracking is often an issue with guitar synths. The Mono Synth features a sensitivity knob which is helpful when we run different pickups through it, with everything but some ancient Teiscos coming through relatively glitch-free. 11 different voices is a lot to unpack, so here’s a quick rundown – bear in mind the control knob plays different roles with each voice and the separate Dry/Synth volumes allow you to control the mix going from subtle pads and washes in the background to cape-wearing lunacy.

From left to right on the Type knob, we begin with Nu Wave, a pulsing modulated string-like synth with a cutoff-frequency filter. Next up is Unison, which gives you saw-wave stacked fifths for when evil chords are the way forward.

Blast reminds us that resonance in the synth world means adding upper partial harmonics (rather than reverb) with a pokey, swept filter. Bass adds a friendly sub-octave to proceedings and as the name suggests, Twin is a dual-filter synth which encourages aircraft-take-off style phasing. XOX is a fast-decay nod to the Roland TB synths of the 1980s and Wub is, in the main, onomatopoeic.

Electro-Harmonix Mono Synth
The Mono Synth’s 11 types are varied and lots of fun, but adding an expression pedal brings out the best in the pedal

The final four settings of the Mono Synth are the least convincing. Despite our best efforts, we fail to find a musical context outside of Celtic freeform improvisation in which the Tinker setting truly shines. Lair and Ghost might be handy for Stranger Things-style soundtrack work, but they fall short of the analogue magic of the ARP Odyssey and Prophet-5 that they emulate. Finally, Blister is a genuinely upsetting sizzle with an adjustable harmonised note in the mix for added sting.

One thing that can take a while to get the hang of is strictly monophonic playing – unless you give the Mono Synth one note at a time, the chances are you will get some random artifacts and strange behaviour. This may, of course, be exactly what you had in mind…

If you have set your heart on making synth sounds with the guitar, then there is very little that anyone can say to stop you. Whether you’re in a 19-piece touring funk band, an avant-garde math-rock collective or you abuse loopers, well, now you play synth. Just make sure you get an expression pedal to unlock the Mono Synth’s true potential.

electro-harmonix mono synth

Key Features

  • PRICE £115
  • DESCRIPTION Monophonic guitar synth. Assembled in USA
  • CONTROLS Dry and Synth volumes, Sens, Ctrl, Type knobs. Bypass and Preset footswitches
  • FEATURES 11 monophonic synth voices: Nu Wave, Unison, Blast, Twin, Bass,
    X0X, Wub, Tinker, Lair, Ghost, Blister. Expression pedal input. Synth and dry outputs.
  • DIMENSIONS 102 x 58 x 102mm
  • CONTACT Electro-Harmonix ehx.com

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