Review: IK Multimedia UNO Synth Pro

The UNO Synth goes Pro, expanding capabilities in all directions – but does it genuinely deserve professional billing? Very much so.

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IK Multimedia UNO Synth Pro

Review Overview

Our rating


Our verdict

Three analogue oscillators with a full suite of FM and control
Two distinct but balanced filters that combine into something greater
Extensive set of analogue and digital I/O
Paraphonic mode expands the capabilities without sacrificing analogue character
Sonically spans essential synth tones, from percussives and bass to leads and pads

Lack of a bundled PSU with the desktop version

Both UNO Synth Pro models are well-thought-out instruments that effortlessly conjure an expansive range of sounds, from the essentials to the experimental, making the most of their analogue sonics and digital flexibility.

Price €649.99 and €399.99 (Desktop)
Contact IK Multimedia

IK Multimedia surprised us in 2018 with the UNO Synth, the company’s first hardware synthesizer. It was analogue, affordable and sounded fantastic. Now, the UNO Synth is all grown up and entering the workforce as the UNO Synth Pro. Bolstering its resumé since its last outing is are: three-voice paraphony, an extra filter, a second LFO, and CV/Gate connectivity.

The UNO Synth Pro comes in both keyboard and desktop formats. Earning the Pro mantle, both versions house exactly the same synthesizer, from the controllers and I/O to the digitally controlled analogue circuits. Both models sport a crisp red and black colour scheme with a dash of green from the backlit arpeggiator/sequencer buttons and the white of the LCD display. They feature a pair of balanced 1/4-inch line outputs, a 3.5mm headphone out, USB and 5-pin DIN MIDI and four 3.5mm sockets for CV/Gate I/O. It’s undoubtedly an impressive set of connections, especially for the more compact desktop version.

IK Multimedia UNO Synth Pro


The keyboard version houses a 37 key semi-weighted Fatar keybed, which along with the metal casing and top-notch pitch/mod wheels makes for a satisfyingly playable yet weighty synth. The desktop version has a flat capacitive keyboard, like the original Uno Synth, and pitch/mod wheel approach. This may not be a pianist’s dream but it is perfectly playable and is 1/8 of the weight, making it by far the better choice for on-the-go producers.


While both models use micro USB for computer connectivity, the desktop model forgoes a DC input for an auxiliary power micro USB socket. The desktop model can receive power from a USB hub or a USB PSU to get the requisite 1.5A. There’s no such issue with the keyboard model – it comes with a PSU.

IK Multimedia UNO Synth Pro


The UNO Synth Pro control surface splits into two areas, the Sound Editing Matrix and the Global Controls. Below these are a row of sixteen numbered buttons overseeing preset bank selection and arpeggiator/sequencer editing. The sound (preset) editing is well laid out and easily navigable. The edit areas, such as oscillators and LFOs, are accessed by a dedicated backlit button. Their four associated parameters light up in the central matrix display above which sit four parameter knobs. The LCD automatically shows the selected parameter, and its neighbouring detented data knob allows for incremental control, and a click entry into a menu-based preset editing system.

The all-important filter cutoff and resonance have dedicated knobs, with the Filter button toggling between the two filters. Besides the above, there are buttons for oscillator mix, filter and amplifier envelopes, the modulation matrix and effects.

The Global Controls area takes care of presets, overall setup, voicing (mono/legato/paraphonic), tempo, hold, and toggles for arpeggiator, sequencer and song modes.

Song mode is a fun addition and lets you chain up to 64 presets and their saved sequences for playback. You can get impressively deep into programming (arp swing and gate, song/step copy and paste) and record sequences quickly. There are more than enough tools on hand, both connective and performative, to make UNO Synth Pro a highly flexible synthesizer.

IK Multimedia UNO Synth Pro


The analogue heart of UNO Synth Pro comprises three oscillators, a noise generator and two filters. The oscillator waveforms are set by a continuous shaper running from triangle through sawtooth to pulse with PWM from 50% (square) to 98%. The LCD shows the selected wave shape as it morphs, which is a fine touch, and one of many benefits of the hybrid analogue/digital approach taken by IK Multimedia.

The oscillators have a ±24 semitone tuning range and are augmented with ring modulation (oscillators 1 and 2) and sync, which synchronises the phase of the second and/or third oscillators to the first. These analogue oscillators sound full on their own, and blend particularly well in the FM mode, getting the creative juices flowing. You can turn out anything from wide basses to mix-piercing leads and even warm, dreamy pads with them.

The UNO Synth Pro is essentially a three-oscillator monosynth, but in paraphonic voice mode, the three oscillators are addressed individually when you press more than one key. If the oscillators have similar settings, you can achieve a three-voice polyphony. More excitingly, when they are set apart – either by tuning or waveform – you can carve all sorts of oddities. This design makes the most of the analogue source, and can also provoke a different approach to programming and playing.


The other major analogue components of the UNO Synth Pro are the two filters. The first is a switchable 2-pole high/low-pass formed around an OTA (Operational Transconductance Amplifier). The second, meanwhile, has 2 and 4-pole low-pass modes and is based on the SSI2164 VCA IC from Sound Semiconductor.

These can be arranged in series or parallel with filter 1 offering a 180º phase position for extra tone shaping, particularly at the cutoff frequency. Between the two filters, there are 24 possible modes within which they can act independently or together via a link and spacing control. Both are high-quality filters with their own flavours: filter 1 is the solid workhorse, while filter 2 brings some self-oscillation bite and scream to the table. Their combined flexibility make the UNO Synth Pro a powerful tool that excels in many areas, from a 303 style ‘beoink’ to smooth pad sweeps.

What’s more, you can route the external mono audio input into the filters, and all that follows. Alternatively, you can bring in external audio post filters and effects.

IK Multimedia UNO Synth Pro

Modulation Matrix

Both filters may be routed to the same ADSR envelope, albeit with independent amounts and polarities, but they can also be modulated via the 16-slot Modulation Matrix. The matrix is powerful and deserves the Pro moniker. Sources include the two onboard LFOs, incoming MIDI/CV signals, keyboard velocity and aftertouch (via MIDI for the desktop version), and most internal parameters, from oscillator tunings to sequencer ties. You can then route these to all the major synthesis parameters and effects levels for wild sound design.

The effects section provides four effects: drive, modulation (three types), delay (five types) and reverb (four types). Drive is limited to just a level parameter, but it can fuzz the edges of a pad or properly blitz a bass. The other three effects match the overall quality well and have about as many parameters as you need. As with the rest of UNO Synth Pro, editing these parameters is simple, and you can approach it from multiple directions without ending in a menu rabbit hole.


The onboard arpeggiator and sequencer are excellent in their own right, but they’re an absolute joy when synced up via CV to modular/analogue gear. The same goes when placing the UNO Synth Pro in a MIDI context, whether as a master device or further down the chain. This is a synth with tons of potential for exploration and growth in performance, composition and production. For those users who outgrow the internal 256 preset slots or want to edit via USB, an editor/librarian app is in the pipeline for a Summer 2021 release.

IK Multimedia has produced a hybrid analogue-digital synth that manages to blend tweakability with an ease of use and sonic quality that justifies the price for the desktop model, especially when the impressive interconnectivity is factored in. The keyboard version may cost more than 50% more, but if you need a high spec set of keys on top, then you’ll be hard-pressed to match the deal, and it does make for a rather tasty instrument on its own.

IK Multimedia UNO Synth Pro

Key Features

  • 3 discrete analogue wave-morphing oscillators
  • PWM, sync, FM and ring modulation for oscillators
  • 2 state-variable analogue filters (one OTA, one SSI IC based) with 24 modes
  • Sixteen slot modulation matrix
  • Two LFOs, two ADSR envelope generators
  • Three FX slots (12 effects)
  • 64 step sequencer and onboard arpeggiator
  • USB/MIDI and CV/Gate (x2) I/O
  • Balanced 6.35mm stereo audio and 3.5mm headphone outputs
  • Audio input for filters, FX or pass-through
  • 37 key Fatar semi-weighted keybed with aftertouch (keyboard version)
  • 32 capacitive-key tabletop keyboard (desktop version)
  • Weight: 5.8kg or 700g (desktop version)

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