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Roland AIRA Compact S-1 Tweak Synthesizer

Synthesizer Module By Robin Vincent
Published September 2023

Roland AIRA Compact S-1 Tweak Synthesizer

Roland’s SH‑101‑inspired S‑1 is a great‑sounding synth with surprising depth.

The Roland S‑1 Tweak Synth is the latest in the AIRA Compact range of fun and fiddly little synth boxes. It’s inspired by the classic SH‑101, and promises to have the same iconic vibe, although it looks nothing like it. Roland use the same Analog Circuit Behaviour (ACB) technology in the S‑1 as they do to build the plug‑in instrument emulations of their legendary gear, and it also forms the basis of the Boutique range of synthesizers. So, it’s probably right to say that the S‑1 is more like a fun‑sized version of the already petite SH‑01A Boutique. However, while it has the same engine and boost to four‑note polyphony as the SH‑01A, the S‑1 also has a few extra tricks up its sleeve.

First Impressions

I like the other boxes in the series, particularly the T‑8 Beat Machine, so I had high hopes for the S‑1. The form and layout are very similar to the T‑8. You’ve got a four‑digit display, and two and a half rows of small, trimmer‑style knobs. It has some buttons and the most miniature two‑octave keyboard I’ve ever seen, and it’s all wrapped up in a rechargeable plastic case no larger than a Korg Volca.

The knobs are fiddly, but that’s not uncommon, so it’s the sort of thing we put up with on good value, mobile little boxes. The white text on the black background is easy to see; however, there’s also text on the buttons, which is far more challenging to pick out. My 52‑year‑old eyes are not the best, but I had to use the torch on my phone to read the text on the black keys. Holding the Shift key illuminates all the buttons in orange, but they flash if they are not enabled so this is only partly helpful. It’s not terrible, I can work around it, but legibility is an important factor, and it’s going to eat into my enjoyment of this little machine. However, after a couple of minutes of playing with the S‑1, I was hooked; this is a delightful little synthesizer.

The Sound

The front‑panel synth architecture roughly follows the SH‑101/01A. It starts on the left with the modulator section featuring an LFO with rate knob and waveform selector, followed by a combined VCO/source mixer section with a six‑octave Range selector, an LFO depth control, and four level knobs controlling a pulse wave, sawtooth, sub‑oscillator and noise generator. Next is the filter section with cutoff, resonance, LFO and envelope depth. Beneath that is a full ADSR envelope. The LFO has the added waveforms from the SH‑01A, but other functions, such as PWM and sub‑oscillator octave, must be discovered via the Shift key.

It sounds very much like a decent analogue synthesizer, and Roland have nailed that SH‑101 tone, but you quickly find yourself going beyond that with the overlapping notes of polyphony and the impressive reverb and delay. The mix of waveforms is excellent, the sub fattens things out gorgeously, and the noise can widen the textures when used sparingly. The filter happily pushes into self‑oscillation and can run as a slightly untuneful oscillator. Just on the surface, there’s a lot to explore, especially once you’ve worked out how to enable the arpeggiator.

The mix of waveforms is excellent, the sub fattens things out gorgeously, and the noise can widen the textures when used sparingly.

Using the two‑octave keyboard is not quite as terrible as you’d imagine. I think it’s a better playing experience than the touch strip of a Volca or the buttons of a Cre8audio East Beast. It somehow manages to accommodate my fat fingers, and having just over two octaves really makes a difference when bashing out a tune. There’s no velocity on the keys, but then there wasn’t any on the original, and you can always plug in a MIDI keyboard for more expressive control. While I was pleasantly surprised by how playable the miniature keyboard is, I would definitely recommend plugging in a proper keyboard. With bigger keys, velocity, four voices, those effects, and the space to play, the S‑1 can feel like it’s playing in the Minilogue leagues.

Preset sounds are folded into a system called Patterns that includes a sequence and modulation data. There are four banks of 16 sounds but only the first bank is populated. They do a great job of showing off the range of this little synth, and if you set it playing you’ll find that switching Patterns is quantised to the tempo, which could be very handy in performance. Sadly, there’s no song mode.

I found one anomaly — or possibly a feature — where any changes you make to a pattern by turning knobs are retained if you move to another pattern and then come back to it. I couldn’t work out a way to return to the Pattern’s saved sound without turning the S‑1 off and on again. I found it particularly frustrating with the otherwise useful Manual button. This button sets the synth to whatever the front panel is set to, which is a brilliant feature, but you can’t get back to the preset sound you were on. I eventually found a solution: the ‘rLod’ command, number 37 in the Menu list, which reloads the current preset. Maybe Roland could make it more accessible — this will be a bit of a theme.

Hidden Depths

The Shift button opens up some of the things that are missing from the front panel. You can set the source and depth of pulse‑width modulation, change the sub‑oscillator octave from minus one to minus two and make it asymmetrical. You can also change how the envelope is triggered and whether the amplifier uses the envelope or a gate. There are portamento settings, polyphony modes, level of keyboard modulation to the filter, and deeper settings for the effects.

And just when you think you’ve got the measure of the S‑1 and you’re enjoying the more‑than‑the‑101 vibe, you discover it has a whole side‑quest storyline to explore. This comes in the shape of the Draw and Chop oscillator modes.

Oscillator Draw allows you to reform the square wave oscillator into something of your own. It creates a stepped or smooth triangle waveform with 16 adjustable nodes laid out on the 16 white keys. You can push each node on the waveform up or down in height to draw in harmonics and tonal changes. Stepped mode is fizzy and aggressive, while sloped mode moves into wavetable territory. A Multiply parameter increases the waveform’s playback speed, giving you a sort of cascading sync sound. There’s a lot to enjoy here.

Oscillator Chop pokes holes in the waveforms. For this, you can use the square, sawtooth, sub‑oscillator or noise and give them all a different Chop pattern. The effect is to bring out overtones and harmonics. You can apply a comb filter to push it into the more clangy territory.

The sound‑crafting possibilities here are marvellous. Once you’ve mastered the tedious menu system, chopping or drawing on the waveforms can take the sound out of the SH‑101 domain and into completely different places. The Comb and Multiply parameters can be accessed from the front panel via the Shift button, so you don’t have to get into the menu to mess with it while you’re playing. Sadly there’s no opportunity to modulate via LFO or envelope, but you could use the sequencer modulation motion lanes to make per‑step changes.

There’s not much to see round the back, with just a USB port and 3.5mm MIDI sockets.There’s not much to see round the back, with just a USB port and 3.5mm MIDI sockets.


The SH‑101 is famous for the immediacy and simplicity of its step sequencer. The S‑1 ignores all the fun you could have had with that and does it in a more versatile but long‑winded way. In step mode, you can turn steps on or off from the row of 16 white keys in banks of up to 64. You then have to laboriously hold each step and dial in the note. Not including the quick‑fire step writing with ties and rests that made the 101 so funky is a missed opportunity, but the flip side is that you also get to include a bunch of other stuff while you’re holding that step. You can dial in velocity, gate length, probability and a sort of sub‑step ratchet effect in up to four slices.

You can also record in real time, and there’s a count‑in and metronome hidden away in the menu system if you can find them. With the four voices of polyphony on offer you can record chords, overdub, or jam along with your sequence.

As well as the parameters you can add per step you can also record up to eight knob movements into your sequence. So, you can add in those filter sweeps, effect plunges, waveform mixes and anything else you can think of. It makes the S‑1 capable of amazing changes and variations throughout a single sequence. But it’s not as nuanced as it could be. Once you’ve recorded in a bit of motion, the S‑1 will fight you if you try to adjust that same knob during playback. The new movement doesn’t override what’s already there and spits at you as it tries to be in two places simultaneously. You can also only clear all the motion data, either per step or for the whole Pattern, so if you get knob motion number eight wrong, you have to delete the lot. An Undo function would be really nice.

The one motion that’s not recorded is, weirdly, the D‑Motion. This gyroscopic technology built into the S‑1 lets you control parameters by tilting and twisting the synth about the place. It’s pegged as a performance device so, I guess, if you wanted something recorded into the sequence, you can just turn the appropriate knob. The D‑Motion is all about picking it up and getting yourself into control.

You activate it by holding the D‑Motion button, and then you have Pitch and Roll mapped to two parameters. These can be modulation, cutoff, resonance, and pitch‑bend on Roll; and pan, expression, delay level and reverb level on the Pitch. It’s a fun thing that some people will enjoy, and the rest of us can ignore without any loss of functionality.


Did I mention how great the effects are? The Delay can offer repeats from 1 to 740 ms, sync’ed or unsync’ed, and can go from phasing to dub and through to ambient without any bother. It’s very well behaved and doesn’t overwhelm or destroy itself even at full‑on feedback and level. Depth is available on the front‑panel knob, which switches to delay time when holding Shift.

Reverb comes with Ambience, Room, Hall 1 & 2, Plate, Spring and Modulation modes. They all sound great, and having just discovered the lovely wavering Mod one, I’m going to be using that all the time. You also get control over time, level, pre‑delay, low and high cut, and density, all through the menu. Depth and time are available on the front‑panel knob.

Chorus is not immediately obvious because it’s buried in the menu. It’s derived from Juno synths and should probably be a bit more front and centre. There are four options ranging from regular, to faster, Leslie and chilled, and they are perfectly good. There’s no depth or time control; it’s just there and does exactly what it should do.

Another sort of effect is the Riser function, which is hidden away in the menu system like the chorus. It’s a very cool rising and falling sound that takes over the Noise oscillator. Once enabled you have a handful of different modes to add riser and downer effects to your sequences. It’s fun and exciting and deserves a button on the front panel. But then many things do, and Roland have had to make a number of difficult decisions to keep to the form factor. Having those features in there, even if only accessible via the hieroglyphs of a menu system, elevates the S‑1 to be much more than it seems.


The S‑1 is a bit of a rollercoaster in terms of its feature set. The keyboard is ridiculously small, but strangely playable; the knobs are tiny, but the sound is fantastic; the sequencer is groovy, but not as fun as the original; the motion capture is exciting, but the clash of overwriting can be disastrous; it has deep levels of waveform editing, but also deep levels of menu diving.

It’s certainly the most interesting synth of the AIRA Compact range...

However, as a playable, tweakable mini‑synth, the S‑1 has an awful lot going for it. Four voices of Roland virtual analogue in a super‑portable, battery‑powered form, with a sequencer you can jam with, editable waveforms and outstanding effects. There will always be compromises in something this small, but it’s certainly the most interesting synth of the AIRA Compact range and it fits perfectly into that line‑up. The experience of using the SH‑101 is so much more than the sound; it’s an instrument, an interface of per‑slider functions that visually represents the sound and invites thorough synthesis engagement. The S‑1 is not that, but it sounds great and stands up as a decent synth in its own right.


  • Sounds fabulous.
  • Four‑voice polyphony.
  • Excellent Unison mode.
  • Great effects.
  • Decent sequencer.
  • Chop and Draw waveform editing.
  • Rechargeable battery power.


  • Menu and sub‑functions can be hard to decipher.
  • Some cool features are hard to find.
  • Motion sequencing prone to clashing with itself.
  • Really needs an Undo button.


The S‑1 starts off as a miniaturised and fiddly take on the SH‑101, but offers so much more that the fun of playing it far outweighs its frustrations.


£169 including VAT.


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