UDO Audio’s highly anticipated debut instrument is a synthesizer with a sound all of its own.

Anticipation for the Super 6 was palpable after its announcement at Superbooth 2019. It may be UDO’s first product but designer and company co‑founder George Hearn is not new to the industry, having previously been involved in the design of the Modal Electronics 008. Nevertheless, a flagship, 12‑voice polyphonic, binaural, analogue‑hybrid synthesizer is an audacious entrance for a start‑up company.

The Super 6 is designed with a firm philosophy. There are no screens and no menus. There is, mostly at least, a one‑knob‑per‑function design. It doesn’t do multitimbrality or have a software editor and it won’t connect to the internet. The design is proudly old school and more than a little inspired by early‑’80s Roland synthesizers like the Jupiter 6, with lots of vertical faders, tri‑position switches and clicky retro‑buttons.

The sound engine, however, is more modern. While it still follows many of the subtractive synthesis norms, there are a couple of headline features. The first is ‘binaural’ mode. Under the hood, the Super 6 has a true stereo signal path. When binaural mode is enabled, the 12 voices are paired to form six true stereo voices. Left and right signals get processed independently and this results in a wide, spacious, almost ‘record‑ready’ sound.

The second clear innovation is found in the two FPGA‑based oscillators. FPGA is fast becoming the norm in digital synthesis and replaces traditional DSP chips, which were often restricted to clock speeds of 48 or 96 kHz. FPGA can run clock speeds at magnitudes faster than these old chips, which means that the telltale aliasing heard in older digital synths is a thing of the past, even when performing complex audio‑rate frequency modulation. In short, these are digital oscillators with all the clarity and depth of analogue ones, and none of the instability.

In essence, the Super 6 represents a modern take on a classic polysynth format. There are two oscillators, two filters, two envelopes, two LFOs, a delay, chorus, arpeggiator and sequencer. There are presets too and even a mod‑matrix, but largely UDO have focused their modernisations on aspects that improve the sound.

Super Good Looks

The Super 6 is available in two colours; the blue exudes a casual demeanour, whereas the black (more of a medium grey in person) feels more business‑like. The 49‑key Fatar keybed transmits velocity and aftertouch and has a lightweight synth action with no annoying clacking sounds. The keys do overhang the main body by about a centimetre, so if you’re moving the keyboard a lot, you’ll need to take extra care not to chip or snap them. For playability, I think this might rank amongst the best synth‑action keybeds I’ve used. I’m less convinced by the combined modulation and pitchbend stick. It is of a similar design to those found in the Roland Juno series. The mod ‘wheel’ has a travel of just a few millimetres and is spring loaded, which means it has to be held in place to be active. Unlike the Roland versions which I’ve played (my SH‑101 has the same design), the resistance feels quite stiff. Occasionally the force needed to apply modulation would cause the stick to fly sideways, applying pitchbend when I didn’t want it. I’m sure, over time, the spring would relax and my playing technique would adapt, but I would have definitely preferred two wheels.

The general layout of the front panel is logical and very well labelled. The raised top half of the panel is home to most synthesis parameters. The bottom half contains the voice setup, arpeggiator/sequencer, mod matrix, patch storage, and effects. The section above the pitch and modulation stick is home to LFO2 and routing options as well as portamento, the keyboard transpose switch and the ‘manual’ button. The manual button switches the Super 6 into a what‑you‑see‑is‑what‑you‑get mode where all the front panel control values are used at their current position; invaluable for learning, or for anyone who thinks patch storage is for wimps.

For everyone else, there are 128 patch storage slots, in 16 banks of eight. These are accessed with the two rows of white/black buttons found just above the keyboard. These buttons are also used for a multitude of other functions such as mod matrix, oscillator waveform selection, sequencer programming and a few setup options. By default, the synth comes loaded with 64 sounds, the second 64 are left empty for you to fill. Whilst 128 sounds doesn’t seem overly generous by the standards of many other modern synths, I think it’s fine. The Super 6 is a synth you’ll want to spend time actually programming, not browsing through thousands of presets. The lack of any screen does make finding specific presets a challenge, though, so anyone relying on presets to recall sounds for a gig will need either a good memory or a notebook and pen.

The star of the show has to be Binaural mode which, along with the buttery smooth DDS oscillators and the high‑class effects, helps to create a record‑ready sound.

Binaurally Yours

Normally, one might move to explaining the oscillators or some other synthesis parameters at this point in the review, but let’s take a small detour to look at Binaural mode. This is such an integral part of the Super 6 that it is worth understanding upfront.

With Binaural mode on, the synth is always processing in stereo. Each oscillator will produce two or more waveforms per voice, each of which travels down its own signal path, through separate twin filters, amplifiers and on to the stereo effects. On its own, this can create a subtle stereo image because the filter and amplifier stages are analogue, so each side of the stereo field comes out slightly different. More pronounced stereo sounds can be made by using Oscillator 1 in ‘Super’ mode, which creates unison sounds by adding six additional copies of the oscillator, detuning and panning them (Super mode is also where the synth gets its name). Furthermore, LFO1 can work in a stereo mode where left and right sides are phase‑shifted relative to each other and applied to the left and right signal paths separately. When you apply this to, for example, pitch or filter cutoff, the stereo image opens up even further.

In order to achieve Binaural mode each note needs two voices, which halves the total voice count to six. In mono modes, Binaural mode is always active. For a more detailed rundown of the various mono and poly modes, see the ‘Voice Assign’ box.

Oscillators

UDO describe the Super 6’s oscillators as DDS — Direct Digital Synthesis. Oscillator 1 (DDS1) offers ‘Super’ mode, which gives you six additional unison voices at the oscillator level. Waveforms include sine, sawtooth, square, triangle, noise or one of 16 single‑cycle waveforms, selected using the 16 patch buttons. These are not wavetables, more’s the pity, but single static waveforms. The Range control allows you to change the octave of the oscillator through six different octaves.

DDS2, the second oscillator, has no Super mode, but offers some different features instead. The same waveforms are available with the exception of the 16 single‑cycle waveforms, which are replaced by a square wave with pulse‑width modulation. There is an additional tuning control which offers +/‑6 semitones. Again, a Range control offers octave‑switching, but the lowest octave is replaced by an LFO mode, where the oscillator is tuned down to subsonic levels and can be used to modulate other parameters using the modulation matrix. LFO mode can also be replaced by a sub oscillator mode which outputs a phase‑locked square wave one octave below DDS1.

The ‘DDS Modulator’ section offers dedicated controls for oscillator modulation. A common theme here, and in many sections of the front panel, are the tri‑position switches which allow you to select a modulation source or destination for the associated slider. It’s worth remembering that you can use the modulation matrix for more esoteric modulations, but these dedicated controls offer a quick way to adjust commonly used modulations. The two left‑most sliders in the DDS Modulator section adjust oscillator pitch with LFO1 and Envelope 1 and there’s a switch to choose between destinations of either or both oscillators.

Moving to the right we find controls for DDS1 Super Mode. Another switch offers off, half or full mode. Full mode means all six additional oscillator unison voices are at equal volume and half mode means the six voices taper off in volume, giving the central voice more presence. There are sliders for detune amount and modulation amount (from either Envelope 1, LFO1 or both). These two sliders also function as PWM controls for DDS2, with the Detune slider controlling Pulse Width and the modulation slider controlling Pulse Width Modulation. It’s a shame that these features had to share controls because it means that you cannot combine DDS1’s Super features with DDS2’s PWM without controlling them both simultaneously. Happily, this seems to be the only place on the front panel where physical controls are shared in this way.

Another nod to those classic ’80s synths is Cross Mod. This offers exponential FM where DDS2 modulates DDS1. This is real FM, as opposed to Yamaha’s DX‑style FM (which is actually phase modulation), and that means that the pitch of DDS1 will move as more FM is applied, which can be annoying. At the moment, there is no preset‑level tuning that can be used to counter this tuning drift, so it’s difficult to use cross mod to alter the timbre of a melodic sound without the whole patch ending up out of tune. The folks at UDO acknowledge this and are considering solutions, so fingers crossed this might be solved in a future firmware update. Nonetheless, Cross Mod is a fantastic source of harsher, clangourous, metallic and inharmonic sounds, plus it can be modulated via the modulation matrix.

The mixer section is quite straightforward. A single knob, by default, adjusts the mix between the two oscillators. It can be switched into a couple of other modes. First is a crossfade mode, which crossfades the two oscillators over a two octave range — DDS1 will play on the left side of the keyboard, and DDS2 on the right, with the crossfade midpoint being moved by the Mix knob. The third Mixer mode is Sync, which forces DDS2 to hard‑sync to DDS1. Sync sounds great, and I found some beautifully monstrous sounds by combining Sync, Unison and Cross Mod together.

Filters & Envelopes

The filter is an analogue, four‑pole 24dB‑per‑octave, low‑pass filter from SSI (Sound Semiconductor). These filter chips are new versions of the SSM2044 chip, designed by Dave Rossum and used in classics like the PPG Wave 2.3, Korg Polysix and Emu SP1200. It is an excellent‑sounding filter with a sharp but stable resonance. It does lose quite a lot of bottom end when pushing the resonance up, but you can use the Filter drive to combat this. The Drive has three settings which overdrive the signal going into the filter by varying degrees. My favourite was the middle position, which mitigated any bass loss due to resonance without losing too much of the resonance character.

There is also a high‑pass filter. It has just one control on the front panel, which switches between off, fixed (at 500Hz) or tracking. When tracking, the high‑pass will track the low‑pass cutoff frequency, effectively turning the low‑pass into a fixed bandwidth band‑pass filter. The 500Hz fixed option is useful for removing muddy low end on patches where it’s less desirable.

A few more front panel controls round off the filter section, with dedicated switches for key‑tracking (off, half and on) and modulation sliders for envelope, LFO1 and DDS2. The audio‑rate modulation of filter frequency from Oscillator 2, I must say, sounds fantastic.

The Filter section flows into the VCA section. There is an envelope level slider, which can be used to overdrive the VCA at its higher position. For amp level, there are options to use either Envelope 2 (the default amp envelope), or a simple gate, or a third option which I like a lot, a gate with release time of around 2 seconds. The latter two settings are useful for freeing up Envelope 2 for other uses. There’s also a switch for enabling velocity sensitivity (off, half or full) and a dedicated slider for LFO modulation of amplitude.

Modulation

The approach to modulation is to offer hands‑on control where possible, backed up by a more in‑depth modulation matrix for more lesser‑used modulation routings. For example, when you want some simple vibrato, reach for the dedicated DDS LFO modulator slider. But if you want to control oscillator pitch from something a little more unusual, say aftertouch, then you can still do so by using the mod matrix. It works by using the same 16 buttons used for patch selection, eight buttons for sources and eight for destinations. Operation is easy: click one of each and adjust the Amount knob. Alternatively, you can also hold a source button, move a slider, and then adjust the Amount knob. It’s a clever way to keep the immediacy of classic analogue synth design whilst adding some modern flexibility. In the mod matrix, the available sources are LFO2, Envelope 1, DDS2, velocity, aftertouch, CV pedal and the pitchbend stick.

I love this implementation of mod matrix. It is very simple and fast to use, but it does come with a couple of downsides when compared with a typical mod matrix accessed with an LCD screen. Firstly, it’s not easy to see what modulation routings are already in a patch. The mod matrix buttons will illuminate to show you what mod sources and destinations are used, but because not all destinations are available on buttons you can’t always see all the modulations that might be active within a patch. The second downside is that not all modulation sources are available. I was particularly upset not to see LFO1 there, because its unique ability to create phase‑shifted left and right LFOs in Binaural mode would be an interesting match for destinations such as cross mod, or delay time. I asked UDO about this and they hinted that there might be some customisation options coming in the future that might allow this. Watch this space, as they say.

Everything seems carefully measured in order to prevent any unmusical outcomes. In fact, it’s very difficult to make the Super 6 sound bad.

LFO1 is the more flexible, whilst LFO2 is generally linked to the modulation wheel for vibrato or tremolo. LFO1 can achieve speeds of 0.05 to 50 Hz, or sync to internal or external clock. Triangle, square, sawtooth and random waveforms are available and you can even use any of DDS1’s 16 custom single‑cycle waveforms. Switch into HF (High Frequency) mode and the range changes from 20Hz to 20kHz. This opens up the possibility of using it as a third oscillator or for FM sounds. In this mode, you can choose to have static frequency, as chosen by the Rate slider, or have the LFO track the keyboard.

Possibly my favourite feature of LFO1 is the ability to alter the phase between left and right channels in Binaural mode. For example, by setting the Phase slider at 50 percent, the two channels will receive LFOs which are out of phase with each other. If routed to something like filter cutoff, this can lead to sounds that swirl dramatically around the stereo field. At lower values, it gives beautiful stereo widening without any obvious differences between the channels. Furthermore, the LFO can be set to delay, freewheel, reset on note‑on, or cycle through only once.

The second LFO is found to the left of the keyboard above the mod wheel stick. Like the first LFO, this one ranges from 0.05 to 50 Hz and can be set to fade in after a set time. Dedicated sliders route it to filter cutoff or oscillator pitch with switches to choose between mod wheel source amount, mod wheel and aftertouch or always on. This section also allows you to route the pitchbend to either oscillator pitch and filter cutoff.

The two envelopes are standard ADSR type. Envelope 1 has an additional Hold section before the Attack for delaying the onset, plus looping, invert and keytracking switches. Keytracking shortens the envelope stages the further up the keyboard you play in a manner similar to some acoustic instruments.

Effects

UDO’s approach to effects is one I like: simple and high quality. The Super 6 boasts a delay and two chorus effects. The delay has just three parameters, level, time and feedback. It has a nice elastic BBD‑style time change so you can have fun tweaking the delay time. All three parameters can be modulated. The delay times range from 1ms to 1s and can be sync’ed to internal or external clock if desired.

The chorus is clearly modelled on the Juno‑6, with two buttons labelled I and II. These can be used individually or together to give three different strengths of chorus. I didn’t have a Juno‑6 handy to check, but they sound as rich and lovely as I remember the Juno chorus to be and, being stereo, they’re a beautiful match for the already spacious sound made by the synth engine.

Arpeggiator & Sequencer

The arpeggiator offers the usual suite of playback patterns, octave ranges and even swing amount. There’s a master tempo knob which offers a 30 to 300 bpm range or, with the external clock option enabled, the arp will sync to MIDI clock and the tempo control will adjust the playback speed in clock divisions. There’s a handy Hold function too, for hands‑off arpeggiation. Overall, a fairly bread‑and‑butter offering, but welcome nonetheless.

A 64‑step polyphonic sequencer is also available, although not at the same time as the arpeggiator. For each step you can program up to 12‑note chords, slides (ties), rests and accents (velocity). The length can be from one to 64 steps. Sequences can be manually started or triggered and transposed by the keyboard. Like the arp, the sequencer can clock to external MIDI clock, at which point the Tempo knob controls clock division.

With sequencer mode activated, the 16 patch buttons become 16 step buttons with four ‘pages’ used to access the full 64 steps. You can program sequences using classic step‑input, or you can program non‑linearly by using the step buttons. Rests, ties and accents are all entered the same way.

One of my favourite sequencer tricks is to set the sequence length to one step, enable Slide on that step, enter a chord, then transpose it using the keyboard. Hey presto: chord memory. With up to 12 voices and all of Super 6’s synthesis, rave stabs never sounded so huge!

Conclusion

If I had to sum up the Super 6 sound in one word, it would be ‘classy’. Everything seems carefully measured in order to prevent any unmusical outcomes. In fact, it’s very difficult to make the Super 6 sound bad. The sound is always sophisticated and elegant. Even the cross mod, which can sound dissonant and detuned, does so with an air of slickness. The Super 6 can sound huge, and fat, and create window‑rattling basses or piercing resonant leads, but it always has this classy sheen that makes everything sound like it’s already been ‘produced’. It wouldn’t necessarily be my first stop for raw analogue brashness, but that’s OK. Not every synth needs to be raw and ballsy. In the end, there is most certainly a ‘Super 6 sound’ and that’s a great thing.

The synthesis engine is intricate, and very flexible. I was able to coax out countless Juno‑esque pads, epic dance plucks, Vangelis leads, resonant techno arpeggios, Berlin school sequences, giant unison stabs, delicate electric pianos, IDM tape‑soaked basslines, rave chord‑memories and more, and I never felt like I’d exhausted the possibilities. It is a complex synth, but it rarely feels like one. There are very few hidden features and the decision not to include a screen almost always feels good. I think that’s a testament to good design. It feels simultaneously familiar, yet new and exciting.

As I said in the intro, the Super 6 is an ambitious synth for a brand‑new company, but I think UDO have pulled it off. They have managed to capture the immediacy and direct connection to the sound of the classic ’80s analogue polysynths like the Jupiter 6 and Juno 6, whilst simultaneously improving almost everything about them. The synthesis is more complex and flexible, and there are features that ’80s synth designers could only dream about. The star of the show has to be Binaural mode which, along with the buttery smooth DDS oscillators and the high‑class effects, helps to create a record‑ready sound. It’ll be interesting to see what UDO do next, but in the meantime the Super 6 might easily become a classic in its own right.