Review: IK Multimedia UNO Synth Pro X – Is this “The One”?

03 Aug 2023 by Rob Puricelli | 4,1 / 5,0 | Approximate reading time: 10 Minutes | Our Rating: 4,5 / 5,0

UNO Synth Pro X Top  ·  Source: IK Multimedia

UNO Synth Pro X Rear  ·  Source: IK Multimedia

UNO Synth Family  ·  Source: IK Multimedia

UNO Synth Pro X & iRig Keys  ·  Source: IK Multimedia

UNO Synth Pro X Editor  ·  Source: IK Multimedia

UNO Synth Pro X Editor  ·  Source: IK Multimedia

UNO Synth Pro X Top Angle  ·  Source: IK Multimedia

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IK Multimedia takes its UNO Synth concept to a new level of control and performance with the UNO Synth Pro X. Is this more of the same or could this be… ‘The One”? 

There were audible gasps and some hesitancy when Italian music tech manufacturer IK Multimedia announced the original UNO Synth back in 2018. Known mainly for producing a range of iOS audio devices and some decent software instruments, many weren’t convinced that they could make the leap to hardware synths. But the team at IK had other ideas. They employed the services of fellow Italian synth designers’ soundmachines to manufacture the internals. The UNO started to garner a following. I recall working on the IK Multimedia stand at Synthfest U.K. when it was first shown there. People came, sat down, played with it for twenty minutes with a big grin on their faces and promptly walked across the aisle to buy one!

UNO Synth Family

Numero Uno

The UNO Synth employed a minimalist interface. It used a matrix-style system with selector ‘buttons’ on the left and rotary knobs on top. The selectors sometimes had dual functions, accessed by a long press. It sounds fiddly, but it worked pretty well. With wave shaping oscillators and a fairly decent filter, it was possible to get some decent sounds out of it. But it had its drawbacks. Firstly, not everyone was happy with the capacitive touch surface. Secondly, the built-in sequencer was very limited at just 16 steps. Thirdly, when powered over USB it was more than a little prone to ground loop noise. This could be filtered out by using a ground loop isolator but it was far from ideal.

Uno, Due…

All that said, it represented decent value for money. After a dalliance with the UNO Drum in the same form factor, the UNO Synth received a Pro upgrade in 2021. It seemed they had listened to a lot of the feedback. However, they didn’t quite address all of it. Headline changes included a keyboard version, an extra oscillator with paraphonic capabilities now possible, and a new, dual-mode filter. The desktop version retained the touch-sensitive keyboard but delivered a lot more buttons for direct access to settings. The matrix system remained, expanded from before.

Once again, soundmachines were responsible for the internals and the UNO Synth Pro did sound very nice indeed. The inclusion of a Fatar keybed pushed the cost up somewhat, and the desktop version still relied on USB power and therefore, ground loop noise could still be an issue. To their credit, they added two micro USB ports, one for data and one for power so with the right USB power adapter (not provided) you could get around the noise.

UNO Synth Pro X Top Angle

The X-Factor

Now, two years later, we have the UNO Synth Pro X. And if I may be so bold, they might just have finally got this synthesizer right. The UNO Synth Pro X is only available as a desktop unit. I am told there are no plans for a keyboard version. However, the desktop unit doesn’t even have a touch-sensitive keyboard, Rather, it has a one octave set of buttons designed for note entry, not necessarily performance. Gone too is the matrix system of parameter control. In its place are 23 rotaries and 66 buttons. This is very welcome indeed because everything is that much more immediate now. It retains the small OLED display with a fair bit of dual functionality on a lot of the controls, but this is very easily accessed.

On the rear we have, as before, full-size MIDI IN and OUT, stereo 6.4mm TRS outs, audio in and headphone sockets, 2 pairs of CV/Gate, USB and power. And those last two are a cause for much celebration. The USB is now of the sturdy USB-C type and the power socket is for a dedicated brick-style PSU. Whilst the USPX can be powered via the USB-C port, its dedicated PSU input is music to my ears.

UNO Synth Pro X Rear

Uno, Due, Tre!

As with the original UNO Synth Pro, the USPX has three wave shaping oscillators with ring and FM modulation. It retains the dual filter design with an OTA-based multimode filter with phase inverting and an SSI-based low pass filter with 2 & 4 pole slopes. These are routed in series or parallel. Three envelopes include one for each of the filter and amp plus a third envelope with no routing that can be used within the mod-matrix. Speaking of the mod-matrix, it’s a 16-slot affair. The two LFOs can be synced and have fade-in and retrigger options. Three effects slots allow you to drop in a decent combo of modulations, delays and reverbs.

So you might be thinking where are the real differences? Well, aside from the much more directly accessible user interface. It really makes for a much more rewarding and pleasant experience when it comes to programming. There’s a new ‘Bassline’ mode which is designed to mimic a 303’s behaviour, not its sound. For example, the upper frequency limit of the filter cutoff is moved from 20kHz to 5kHz. It also mimics the filter envelope amount with a higher minimum limit. Furthermore, it brings in two extra features; accent and accent decay.

Like I said, it doesn’t mimic the sound but it gives you more of a TB-303 programming experience.

Editor & Librarian

As with all previous UNO synths, the USPX comes with a librarian/editor application for Mac & PC which works as a standalone or plug-in. This has always been a great feature of these synths so I’m glad to see the tradition continuing. UNO Synth Pro patches are NOT compatible with the UNO Synth Pro X. The file extensions are different and I can only assume that the few differences between the two synths are significant enough to render the patches differently.

Once again, the inclusion of an editor/librarian that works as a plug-in is incredibly useful. Unlike previous versions, where the editor exposed much more of the synth’s capabilities, the Pro X editor doesn’t have to do so much of that anymore. It really is a highly useable synth in its own right.

UNO Synth Pro X Editor

In Use

On paper, and possibly from this review, you might well be wondering how this differs from the previous UNO Synth Pro. The answer is not much if you don’t consider the completely new user interface. There’s an extra ADSR envelope, Bassline mode, the very welcome USB-C port and dedicated PSU, some minor tweaks to the FX and that seems to be it. So why would you buy this over the non-‘X’ Pro?

For me, the UNO Synth Pro X represents a physical evolution of its predecessors. Each iteration has added something to the product line. The jump to the original Pro was a big one and its capabilities over its smaller sibling certainly justified that ‘Pro’ label. It was more of everything. Much more. And the inclusion of a keyboard model saw IK Multimedia sidling up to the bigger players in the market. It gained a lot of fans, including some high profile ones. However, the user interface still lacked something.

More Is Less

For all that sonic power, the original UNO Synth Pro was just a bit fiddly to dig in there and really play with. And this is where I believe the Pro X has really seen this concept finally come of age. The very joy of analogue synthesis is the ability to just leap in, grab stuff and wreak immediate havoc on the sound. If you had to go through a few steps to get to that parameter, diving through a matrix-style editor or menu, you immediately lost the fun. It was all very well putting the most common controls front and centre but not everyone responds to those.

UNO Synth Pro X & iRig Keys

The envelopes are very snappy and feature the same loop and retrigger settings as the previous version. The third extra envelope can be assigned to pretty much anything you want from within the mod matrix. And the SSI-based filter is a whole heap of squealing fun! The USPX ranges from a lovely, warm, thick sound to one of a wailing banshee. This is achieved much more rapidly thanks to the immediacy of the new UI. And that UI stands out much better in the dark with the inclusion of a variable brightness backlight. Perfect for both studio and live use.

Effects & Other Features

When it comes to effects, there isn’t a huge choice, much like its predecessor. There are a selection of modulation, decay and reverb FX that are all very good. The spring and reverse reverb from the previous model are replaced by a trendy shimmer. Instead of the phaser and flanger, a Uni-Vibe style effect has been added. One other very cool feature is VCA Amount. This can be set as a percentage with 100% allowing the VCA to be fully modulated from the envelope. 0% allows the VCA to remain fully open. This is particularly useful for creating drones.

Other small changes or improvements include the ability to recall just a patch or just a sequence. These two things were inexorably linked in the UNO Synth Pro. Factory presets can now be restored from the synth itself. Very handy!

In Conclusion

The UNO Synth Pro X finally delivers a true hands on experience. There’s no matrix editor to navigate, no screen menus to scroll through when all you want to do is dial up the SSI-based filter’s resonance and make that thing scream. Right out of the box, I found myself having way more fun with the Pro X than I did the original Pro. Every control is immediately obvious and I barely read the manual for the first week or so. Minimal manual reference is an important benchmark for me. If I can dive in and start having fun without constantly checking the manual, I’m happy.

It is my belief that with the Pro X, IK Multimedia have finally got the UNO Synth right. That’s not to say that the previous incarnations were in any way poor. It’s been an enjoyable journey and I’ve always loved each step. The Pro X feels like a proper synth now. I’ve barely noticed the lack of chromatic keyboard.

The lack of said keyboard certainly forces you to play more with the sequencer, and it is a great sequencer to play with. It’s simple and straight forward to use and those 48 lanes of parameter automation per step really allow you to shape the sounds wildly throughout. It also features a sequence randomizer that will select and place notes in the sequence at random based on the key you have the sequencer in.

Is It The One?

If you’ve been holding out on buying an UNO Synth Pro, then you have been justly rewarded for your hesitancy. The UNO Synth Pro X is a ton of fun from the get-go. If you’re already an UNO Synth Pro owner, you might struggle to justify the outlay but I promise you that if you can, you will not regret it. It’s taken a while for IK Multimedia to refine their first synth into something that strikes a balance between delivering a powerful, malleable sound with intuitive, easy-to-use manipulation. But they’ve done it. The UNO Synth Pro X deserves to be recognised as a great analogue synth.

More Information

The IK Multimedia UNO Synth Pro X is available now for €589.00. The UNO Synth Pro X Editor/Librarian is free for all registered UNO Synth Pro X users.

• IK Multimedia Website
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