Dewanatron Swarmatron

Analogue Synthesizer

Published in SOS June 2011
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Reviews : Synthesizer

This is a synth like no other, eschewing conventional controls, nomenclature and even an ordinary on/off switch. Is it destined to become a cult classic?

Paul Nagle

Dewanatron Swarmatron

Dewanatron make electronic instruments that are deliberately unusual. Not only do their analogue creations resemble something HG Wells might have dreamed up, the strange sounds they make are surely ideal for scoring The First Men In The Moon, or War Of The Worlds.

A small family firm, the Dewans not only make instruments but perform with them too. Judging by some of the web site demos, this far-out and thoughtful music offers a fascinating insight into the company and its creations, which are intended "to make music in real time, suitable for concert performance, live recording, or to be broadcast over the airwaves.” Plastic digital workstations, piano samples or some marketing department's 'next logical progression' are definitely not what Dewanatron are about!

What It Is

The Swarmatron is an analogue synthesizer offering dual ribbon control over the pitch and separation of eight sawtooth oscillators. With a simple architecture that includes an ADSR envelope and a low‑pass filter, it's in performance that the Swarmatron comes to life.

Just as I couldn't pick up a violin and make it sing, I doubt anyone will master the twin ribbons overnight — but when you begin to pick out simple melodies and eerily morph them into chords, it's impossible to avoid the word 'unique' for long. Granted, there are some conceptual similarities to the Theremin and Ondes Martenot, but that's an oversimplification, as we'll see.

Wood Be Nice

The Swarmatron's front‑panel controls are cryptic, to say the least, so for once there's no shame in reaching for the manual!The Swarmatron's front‑panel controls are cryptic, to say the least, so for once there's no shame in reaching for the manual!

Made from poplar, then stained and finished with polyurethane, the Swarmatron could have been lifted straight from a 1950s boutique furniture catalogue. The finish is superb, those gently‑rounded corners quite unlike anything found on a modern, mass‑produced synthesizer. It therefore came as no surprise to learn that one of the Dewans used to build furniture for a living. Imparting a hardy, industrial texture, a green glaze of Hammerite paint forms the panel's distinctive backdrop.

At a curvy 56 x 38 x 19cm and weighing around 6kg, the feeling of handling a 'real' instrument is unshakable from the first touch. I loved the quality of the knobs and their generous spacing but I thought that perhaps the small, round, black switches weren't the optimum choice, partly due to their loud physical 'click', but mostly because their on/off status isn't as clearly visible as you'd like. The Dewanatron web site shows a model with Prophet‑style buttons, each with an integral LED. This would seem to be a good alternative, if perhaps not so stylish. I was also wary of the exposed connection wires for the ribbons — it seems an unnecessary risk to bare these quite so boldly to the world — and the gently curved wooden frame doesn't make adding a protective lid especially easy either. I can hardly believe I have another small niggle too, but I do. The tiny adjustment screws for the ribbons and oscillators are accessed by fairly ugly holes that I'd certainly want to cap. And, perhaps in keeping with its 'old style' design, the mains cable is fixed rather than detachable, which I've always found to be awkward.

I don't want to overstate these observations, though: this is a gorgeous instrument, clearly made with loving care. Unusually, you switch it on with a key. This is a vital object and one you'd be wise to duplicate in case the drummer feels like pinching it after a few sweet sherries. With no key, you're left with a rather magnificent ornament. The key is an innovative security measure, and I imagine Synthesizer Patel himself would heartily approve.


At the back of the Swarmatron are the quarter‑inch audio output and the trigger input socket.At the back of the Swarmatron are the quarter‑inch audio output and the trigger input socket.

With no precedent for how I should play the Swarmatron, I began turning knobs and drawing my fingers along the ribbons. I didn't have the manual at first, which turned out to be a blessing in disguise, because it prompted me to stumble around the old‑fashioned way, trying out everything to see what happened. I discovered several particularly enigmatic controls, such as the knob marked simply 'C' and the switch selecting either 'X' or 'F/SW'. Several places on the panel were even marked with the same letter ('F' and 'R' were popular) but I quite like a bit of mystery in my instruments. At least the longer of the two gently‑sprung ribbons proved relatively straightforward: it controls the Swarmatron's pitch.

Having connected the single audio output, probably the most logical place to start is at the eight black switches spread across the top of the panel. These correspond to the eight analogue oscillators that can be kept in (almost) unison or stretched apart to produce strange chords of equidistant pitches. Clicking each switch forwards turns on the corresponding voice — so I began by switching off all but the lowest. This left a bright analogue sawtooth wave whose base frequency was determined by the leftmost 'F' control. The oscillator's range goes happily off the scale in both directions, subterranean basses for Morlocks smoothly sweeping up into frequencies beyond my hearing.

In order to play the ribbon, you should first tune its lowest position with the 'F' control. The ribbon's range is set by a control marked 'R', the one nearest to the end of the ribbon. By positioning a finger at the highest spot and tuning the highest note you intend to play, you're ready to go.

Presumably due to this great freedom over the pitch range, the wooden block supporting the ribbon has no finger position markers, so pitch accuracy is a matter for your ears and fingers alone. I found that setting an overall range of about an octave and a half or two octaves gave me a reasonable chance of picking out simple tunes. But much wider, more experimental ranges were fun too! String or theremin players would doubtless adapt far quicker than I. To home in on exactly the pitch and range needed, two fine‑tune controls — the elegant, multi‑turn 'CVF' and 'CVR' knobs — were very welcome and never far from my fingers. I later learned that these aren't fitted as standard, which is a pity, because I'd rate them as damn near indispensable. If you value such fripperies as accurate pitch tracking, whether via ribbon or an external voltage source, you'll need to add a further $200 to the Swarmatron's price.

Having swept and wiggled my way through a few basic melodies, I've got to admit that neither my sensitivity for pitch nor my rocking‑finger vibrato is going to bring tears to many eyes — except tears of pain, perhaps. Rather than perfecting my technique, I thought it high time to experience the lushness of additional oscillators. Here's where that mysterious 'C' switch comes into play. Unknown to me at first, this 'Cluster Preset' control has just one setting that puts the shorter of the two ribbons into Swarm Mode. When in this mode, the oscillators can be spread out over almost the whole audio spectrum. Four of the five available Cluster Presets (all of which are unmarked on the panel), force the oscillators into preset tuning intervals — a process that disables swarming entirely. These preset intervals are ideal for a spot of normality; they offer unisons, major thirds, fifths and major sixths. But it's the Swarm setting that gives the Swarmatron its unique sound, and, of course, its name.

Swarming Up

On the right‑hand side are CV inputs for 'Swarm', filter cutoff and pitch. On the right‑hand side are CV inputs for 'Swarm', filter cutoff and pitch.

Having started to get a feel for the upper ribbon, my dexterity was challenged afresh by the lower ribbon and its uncanny ability to push the oscillators from unison into bizarre, twisted intervals. The vital knob here is the Swarm Control Range, another of those marked simply with an 'R' (this one is positioned next to the central 'X' or 'F/SW' switch). This terminology isn't as complicated as it initially sounds. In fact, you soon forget all about it, and even the various panel labels, and seek, instead, the position of controls by feel. These very quickly become a natural extension of the instrument, a rare feat on modern gear.

At first I wasn't attuned to hearing all the intervals accurately, so I switched on two or three oscillators only. Playing the upper ribbon and then adding note swarms with the other is a remarkable experience — but not one for the faint‑hearted. The manual describes the stretching of one note into an eerie chord as "taffy pulling”, a term open to misinterpretation in some areas of the UK. Taffy pulling can lead to wild, bell‑like tones one moment and the ominous buzzing of a hive of bees the next. I even coaxed some near-choral effects from it, although I'm not sure I could ever get them back again!

Setting the tuning and range of the two ribbons is a skill that takes time to acquire — so it's fortunate that you can return to (relative) safety, or at least conventional pitch‑spacing, by selecting one of the previously‑mentioned Cluster Presets.

I found the ribbons to be very responsive: if dragged smoothly, the pitch slides are seamless, but if you apply pressure as you slide, the pitch can be made to wobble all the way. Dewanatron recommend a guitar-string lubricant to render playing as smooth and frictionless as possible. Looking closely at the ribbon, I noticed it consisted of several layers so I asked about them.

"As far as what does what, the vinyl on top is there to provide a smooth, finger‑sliding surface. The two black ribbons underneath serve to sandwich the wires feeding them the potentials along their length (which is the best way to form a reliable contact in this case). And, as resistors in parallel, they add up to an ideal impedance for the circuitry they feed. For the pitch ribbon, the two strips of metal they contact are for the pitch potential and the ADSR trigger.”

Analogue Heaven

At its heart, the Swarmatron is a monophonic analogue synthesizer with eight oscillators and a state-variable low‑pass filter. The filter is a little Moog‑like at times, or perhaps reminiscent of some of Roland's early filters. Its base frequency is dialled up by a similar technique to that of tuning the oscillators' lowest pitch. It involves a single control: 'F'. Adjacent to this, the 'Q' knob is the filter's resonance.

With the central switch in its upper position ('X'), the upper ribbon controls pitch and filter cutoff simultaneously. When the switch is set to 'F/SW', the lower ribbon is relieved of its swarming duties and takes control of filter cutoff instead. In this mode, the large central knob sets the swarming amount. This fabulous, super‑smooth control is way more precise than the ribbon where swarming is concerned, and offers whole new dimensions of chordal subtlety. Be aware that if you sweep the lower ribbon downwards and release it, there may follow a few puzzled moments as you wonder why everything has gone quiet. The cutoff stays at the value last set by the ribbon, and it's quite possible to set this so low that it effectively closes the filter.

The control marked simply 'N' sets the filter's bi‑polar envelope response. And for dramatic tonal changes, filter drive, 'D', overdrives the filter to produce "complex and chaotic waveforms”. At high levels of drive and with high resonance, this pushes the Swarmatron beyond edgy. It can even silence the instrument for a few seconds, which was worrying the first time it happened!

The envelope is a familiar ADSR type shaping the output level and filter cutoff. Any note played during the envelope's release phase seamlessly blends in for that fluid analogue signature sound that is still beyond the reach of many software envelopes. If you set a fast attack and play rapid bursts on the pitch ribbon with both hands, the Swarmatron is transformed from spooky space violin into mental metal percussion. Give it a wide swarm range and turn on lots of oscillators, and the resulting atonal cacophony can be truly unsettling!

You quickly work out the purpose of other, more conventional controls: activating the 'T' switch makes the filter track the base pitch, with the amount (and direction) of tracking set by the knob in the top-right corner. Of the remaining controls, the top left-hand knob marked 'V' is an easy one: volume. The adjacent white button is a sprung mute: push it down to temporarily cut the audio output. Which leaves just two final switches to flip...

External Control

I was getting quite hooked on the idea of cryptic labelling, but even so, the switches labelled 'A' and 'B' stopped me in my tracks. The manual revealed that these govern how the Swarmatron is triggered, and this meant that it was time to consider some of the sockets at the rear and side.

Essentially, different combinations of switches 'A' and 'B' enable external triggering, ribbon‑based triggering or both. With both switches off, only the ribbon can trigger the envelope. If both are on, a +5V signal received at the rear 'Trig In' jack is needed for triggering to occur. The remaining two switch combinations define conditions in which the ribbon either interrupts external triggering or is a pre‑requisite for it.

This selection of choices opens up an alternate list of performance tricks — for playing in sync with sequencers, drum machines and so on. I especially enjoyed jamming in the mode where playing the ribbon interrupts triggering — take away the finger and the external triggering kicks in. Or, with a flick of the switches, the incoming pulse is ignored until you touch the ribbon. It's very flexible, and even more so when combined with the three CV inputs at the right-hand side.

Under external CV control, the Swarmatron is a whole new breed of fun puppy — one that's far more chromatically obedient and capable of tricks my novice fingers could not replicate on a ribbon. The CV inputs are calibrated for 0‑10V, so I connected up my faithful Kenton Pro 2000 MIDI to CV interface and away I went. The are CV inputs for oscillator pitch, Swarm amount and filter cutoff. Driven from a sequencer or keyboard, you can therefore produce actual bass lines and melodies. When you add swarming into the picture, the warped intervals of those analogue oscillators take us, once again, far from the path of normality.

I fed in an LFO from my Digisound modular to the Swarm input, causing a gentle sweep of oscillator pitches. Later I sent fast sequences of notes and filter cutoffs, punctuating the resulting pattern with a further loop of swarm values that generated occasional chords. Wild stuff! As in manual performance, you adjust the Swarm Range via its dedicated control and I did ponder what it might be like if this, too, was accessible via a CV input. However, I think the existing inputs are sufficient for most sequencing needs and for interactive, sync'ed‑up performances.


There are an increasing number of modern gadgets posing as musical instruments that enable you, and anyone else, to sound absolutely splendid with the minimum of effort. The Swarmatron is not one of these. In a way, it reminds me of the EMS Synthi — not for any sonic reasons, but for the sense of it being alive, of being a creature whose personality has to be discovered.

Wayward, unpredictable, unconventional, the Swarmatron wouldn't seem out of place in my grandad's workshop, amongst the dismantled radiograms and antique clocks. There are a few areas ripe for improvement, though. Firstly, I feel the multi‑turn tuning controls should be included as standard, and for peace of mind, I'd like to see some protection for those exposed wires and a safety cover for the ribbon. For live performance, a sturdy flightcase will be essential, and I'd recommend getting a spare key cut — just in case! I did manage to silence it accidentally on a couple of occasions. Odd combinations of controls, or merely my lack of experience, tended to be the cause, but this reinforced the feeling of a synth not for the faint‑hearted. It requires a serious commitment of time and money but is far more than merely a synthesizer controlled by ribbons. The swarm effect is particularly weird and wonderful, whether for conjuring up alien ensembles or for explorations 'beyond the theremin'. And if ever an instrument was begging to be used with a looper, with a pile of stomp boxes, with every effect under the sun, this is surely it. For more earthly electronic tones, crank up the resonance and drive and the musical filter becomes quite edgy. Factor in external CV control and its squelch can be sequenced to yield synth basses and leads.

Even though the vast majority of what I achieved was closer to sound-design madness than 'normal' music, I'll be sad to see the Swarmatron go. It wasn't always easy — or possible — to get exactly the same sound twice, so I found taking samples or recording short performances became a natural way to incorporate it into tracks. I am starting to find its sweet spots, though, and developing some kind of technique. So despite it being out of my league financially, I have no doubt the world is made considerably richer by its presence.    

Dewantron Swarmatron $3250$3250
A remarkable‑looking, warm‑sounding and yes, unique, electronic instrument.
Its swarm effect is refreshingly different.
It's a non‑keyboard‑based analogue synthesizer.
CV inputs for more 'normal' or sequenced operation.
Not for the light of attention or shallow of pocket.
The precision fine‑tune controls are chargeable extras.
Its odd nature could restrict it to those with a generally wayward mind‑set.
The ribbons and their wires are a little exposed.
Better be sure nobody nicks that key!
A strange and beautiful synthesizer with its very own trademark 'swarm' effect. While it won't slot in seamlessly to existing musical styles and it requires patience and effort to learn, the Swarmatron is nevertheless a rare and distinctive addition to the world of electronic music.

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