Roland S-1 Tweak Synth is the most compelling member of the Aira Compact family

Last year during Superbooth Roland unveiled the Aira Compact series – its first true competitors to Korg’s wildly successful Volca line. Now the company is back for Superbooth 2023 with a new addition to the family, the S-1 Tweak Synth. Like the T-8 and J-6, the S-1 uses Roland’s Analog Circuit Behavior (ACB) technology to recreate the sound of an iconic instrument from its past, the SH-101. While the core of the S-1 is ultimately quite familiar, in true Roland fashion there’s a lot of modern features packed in as well. And in even truer Roland fashion, many of them are buried in a bewildering array of indecipherable menus and button combinations.

I’m going to get this out of the way right now, because it’s a recurring theme in almost every review I write of a Roland product. The interface here is truly mind boggling once you get beyond the immediate hands-on controls. Almost every knob and button has at least one shift function. Many of them aren’t labeled. And the only visual feedback you’re given for anything is via a four-character, seven-segment LED display. A seven-segment LED display in 2023! I dare anyone to tell me what the hell “Nod.d” means without looking it up in the manual. And what about the D-Motion button suggests that this is where the probability and substep options are located? I’m not trying to suggest that I should be able to figure out every feature on an instrument right away without reading a manual. But I also shouldn’t feel like a lost ball in the tall weeds. Especially not when we’re talking about an entry level $200 synth.

The clunky interface here is particularly frustrating because the S-1 is otherwise kind of great. It actually has a decent amount of hands-on controls. It offers far more depth than any of the previous Aria Compact entries, even if you never touch the shift button. There’s an LFO with six different waveform options, including random. The oscillator section allows you to blend together a saw and square wave with pulse width modulation, as well as a sub oscillator and noise source. And, unlike the original SH-101 which was monophonic, the S-1 is polyphonic so you can play actual chords (up to four notes).

And the oscillators sound great. I’m not always the hugest fan of Roland’s ACB sound engine, but it shines here. Thick bass, acid leads and 16-bit JRPG arps are all easily attainable and satisfying. This is easily the best sounding member of the Aira Compact family.

The filter is excellent too. It stops just shy of self oscillation, but still gets pretty sharp and can certainly endanger your eardrums if you have your headphones up too loud. But at the lower end of the cutoff spectrum you get a surprising warmth and silkiness from this dirt cheap emulation of a classic analog circuit. 

Roland even threw in a delay, seven reverbs and four chorus options. The reverbs are merely ok, but the delay is a perfectly solid digital effect. You can even set the delay time to 1/128 and crank the … Anb(?) reverb model to get howling metallic textures that are out of this world. The choruses, pulled from the Juno and JX-3P are truly excellent. It’s just a shame they’re buried in the arcane menu system because I want to turn them on for almost every patch I make.

There’s a solid arpeggiator, and you can even record directly from the arpeggiator into the 64-step sequencer. That’s pretty handy for laying down glassy high notes then going back in and overdubbing some bass to accentuate the chord changes. I will say though, I haven’t quite figured out how to get to 64 steps. By default sequences are 16 steps, there is no obvious way to go beyond that and I was not provided a manual with my review unit. 

Roland also added motion sequencing to S-1, so you can tweak settings as you’re recording to slowly increase the amount of delay over the course of a pattern. Or even go into the menu and turn on and off the chorus, or change the sub-oscillator tuning on a per-step basis. It really opens up a lot of possibilities on an instrument this small and affordable. You can ratchet notes, set per step probability, and there’s even Step Loop for quickly mangling your sequence into new riffs on the fly, though that is far more useful on a drum machine.

If the feature list for the S-1 ended here, that would be perfectly fine. But Roland added more. So. Much. More. Maybe too much more.

There’s a draw and chop function, which allows you to create custom waveshapes for even wilder tones. Then use the multiplier on your freshly drawn waveshape, or the comb on your chopped wave for hard-synced and dissonant metallic noises. You can also turn the noise source into a sort of pulsing riser effect. Though, I was unaware of this when I accidentally activated it while messing around one afternoon and couldn’t for the life of me figure out what was going on. This is one of those many unlabeled features hidden behind a seemingly arbitrary button combination. (For the record, you hold down shift then press 1 and 2 simultaneously to cycle through a few different riser modes.)

The one last feature worth mentioning (I think), is a bit of a head scratcher. D-Motion allows you to change parameters by picking up the synth and tilting it about. It’s a fun novelty for a few minutes, but it doesn’t feel practical. Though, at least it makes more sense on the small, battery-powered and portable S-1 than it does on the SH-4d.

Beyond that the S-1 resembles the rest of the Aira Compact line. It’s plastic, has a rechargeable battery built in and weighs next to nothing. There are 3.5mm MIDI, sync and audio jacks for connecting other gear. And USB-C for charging, but also for sending audio and MIDI to computers, phones and tablets. My one other minor gripe, physically at least, is that the mushy keys are painfully small. Playing chords on this thing is a bit of a headache. But not much more so than on any other instrument of this ilk, like the Modal Electronics Skulpt or a Volca Keys.

The S-1 Tweak Synth is both the most compelling and most frustrating member of the Aira Compact series. It has plenty of hands-on controls, sounds great and is deceptively powerful for the price. But it is also, perhaps, too complex. It tries to do too many things and ends up feeling cluttered and confusing. Which is the exact opposite of what you want from what is essentially a $200 music toy.

What made Korg’s Volcas so successful wasn’t their laundry list of features, it was their simplicity. They sounded good enough, were affordable, and unintimidating. Roland seems to have gotten the first two parts of the equation down. Now it just needs to work on the last ingredient.