Beetlecrab Tempera

Beetlecrab introduce their own distinctive take on granular synthesis.

Believe it or not, it’s surprisingly difficult to pin down Beetlecrab, the Prague‑based developers behind the Tempera. For one thing, the company have given each of their two available instruments, the Vector and the Tempera, its own website and even its own contact email address, with the landing page of the company website proper simply guiding users to either of the above. “Another thing we’re slowly dealing with is the inscrutable situation about our branding,” reveals a candid blog post from August 2023. “It’s a mess. To get out of all this confusion we decided to adopt an umbrella for both existing and new upcoming projects: beetlecrab.audio. We couldn’t quite figure out a suitable name but many of you started using this, so let’s go with it.” Such an unfussy and atomised approach is refreshing. Clearly the Beetlecrab crew are far more concerned with creating instruments whose value is based on merit alone and not on brand recognition or the success of other units in their range (which, in fairness, is a very small range). No slathering of the company insignia across the audience‑facing panel here; indeed, the developer’s name isn’t inscribed anywhere on the chassis of the Tempera. As far as I can tell, they have no logo of any kind.

In a line‑up, the Tempera would look very much at home next to the likes of the Ableton Push, Polyend Play and OXI ONE, but its similarities with these units more or less end there. A standalone polyphonic granular synthesizer, its grid isn’t principally a control interface or a sequencer — it has no sequencer at all, in fact — instead, in many ways, it has more in common with a tape machine than it does with other digital hardware. Across the top of the unit are four encoders, which represent four ‘emitters’ with four different colours. Each of these emitters is essentially a standalone granular synthesis engine, complete with its own volume, behaviour, modulation, effects and more. I daresay — and this will make more sense in due course, so read on — that even one of these emitters would be enough to render the Tempera an impressive instrument, let alone four.

Cellular Network

The other central component to the Tempera’s workflow is its 8x8 grid of light‑up cells. This is best thought of as a sound bank to be accessed with the four granular engines. Each vertical column of eight cells, or track, represents an audio file with the playback direction going from top to bottom. Select an emitter — blue, pink, yellow or green — and touch a cell to illuminate it in that colour. Play a note, and that emitter will output that particular cell’s worth of audio according to the settings of its granular engine, which cover pretty much all the things we love about granular synthesis: grain time, grain density, jitter, tuning variance and so on. You can set the behaviour of the emitter to toggle on and off, latch or instantly disengage upon release (‘Instant’). The latter means you can hold a note and draw your finger back and forth through the audio file to generate some incredibly expressive and flexible granular goodness — already far more spontaneous and expressive than you’ll find in most synths of the Tempera’s type.

But here’s where things get interesting. As well as drawing a finger up or down through one audio file, you can of course draw it left or right and into other tracks, pulling in audio from different samples whose equivalent cells will be played back with the same emitter settings. Things don’t stop there: I’m not going to simply list all the emitter parameters, but there are also settings for things like Spray, which momentarily scatters emitters across the grid from the centre of the initial cell — vertically, horizontally or both — residually triggering grains from other cells. It’s also possible to modulate emitter movement and therefore create complex but repeatable routes. You could set one emitter to Toggle and set another to Instant to add all manner of spontaneous complexity on top of an otherwise consistent timbre. You could set a third emitter to trigger its own audio with less low end and less of the Sides channel (yes, there’s Mid‑Sides as well as left‑right panning). Four emitters to play with across eight audio tracks really is an astonishing amount of flexibility. I could go on and on.

Ambient washes of skittering atmospheric grains are easy to the point of immediacy with most sounds, but it’s also possible to play samples in a more considered way...

‘OK’, I hear you ask. ‘That’s all very interesting. But what does it sound like?’ In many ways, that’s a good question: it all depends on what source audio you’re working from, what you’ve got where on the grid of cells and how you’ve set each emitter. Ambient washes of skittering atmospheric grains are easy to the point of immediacy with most sounds, but it’s also possible to play samples in a more considered way, augmenting it with the texture and tonality of other sounds on your canvas. In this sense, it’s accurate to say there is an ‘obvious’ way to use the Tempera, but it’s by no means limited to this more conspicuous functionality if you take a little time to learn quite how deep it goes. Let’s say you’ve got three adjacent tracks on the grid with an extract of a choral piece, a sequence of drum sounds and a sampled piano chord respectively. If your emitter has a little Spray engaged, it could pull in intermittent piano and choir sounds while spitting out pitched, percussive clusters of drums, adding a wholly different dimension to an otherwise rather one‑dimensional sound. With spatial effects engaged, even the briefest ghost of a granule from another track can trigger some gorgeous residual textures. Best of all, I found sounds like this to be playable melodically as a synth voice or used as a more textural tool with more or less equal effectiveness.

It’s also worth making mention of the fact that, alongside being able to import audio files and record in mono or stereo via a line input on the rear of the Tempera, it’s also possible to resample from its master bus, wet or dry, and even record acoustic audio via an onboard microphone. This side of the Tempera is brilliantly thought out; not only can it detect the base frequency and bpm of a sound, it can also normalise audio to bring it up to level. I would have loved the Tempera to be able to process live audio through its granular engine like the 1010music Lemondrop can, but that’s less a criticism and more a suggested bonus for a future firmware update. Considering its size and lightweight build (despite a sturdy powdered‑metal chassis), the Tempera is certainly a backpack‑friendly sampler on top of the rest; though on this note I couldn’t but mourn the lack of a battery, which would have opened up masses of potential for sampling and sonic sketching in the field á la Roland’s SP‑series samplers.

On the Tempera’s back panel we find a power switch, 3.5mm MIDI I/O, USB A and B ports, and three quarter‑inch sockets for audio in, out and headphones.

Art & Design

Following the fact that the Tempera is named after a painting technique it makes sense that emitters, samples, effects and so on are saved together as a ‘canvas’. It’s a great term for it, since it really does feel, upon opening a new one, like facing an endlessly editable and highly inviting, well, blank canvas. The Tempera can accommodate a microSD card or USB storage device, but it also has 8GB of onboard memory, so there’s all the space you could need for storing and recalling canvases.

While the Tempera is at heart a keyboardless synth, very much at home with an external controller (over USB or either type of TRS MIDI, usefully), it’s also possible to allocate varying portions of the grid, or the whole lot, to trigger notes like a keyboard and thus render it self‑sufficient. The Tempera does well to accommodate this as best it can while maintaining the cell grid’s principle function of hosting emitters across its audio tracks. Ultimately, it does require a decision to be made about how much of the grid should be left over for that main purpose, but that simply depends on what you’re using the synth for. It’s also very quick to adjust this thanks to a dedicated button for keyboard settings.

In the compositional or sound‑designing sense, I found it most convenient to use an external keyboard, being a keys player. But the Tempera’s overlaid ‘keyboard’ can also be quantised to scales if desired, opening up the kind of gestural, no‑mistakes‑possible playing a conventional chromatic keyboard could not. It’s possible to have the keyboard cover just a couple of rows (along the bottom, top or either side), any half of the grid or the whole lot. This I found to work very well. If your emitters have been placed and have no need to be edited, you can then essentially turn the whole grid into a control surface (hence my earlier disclaimer about it not being principally a control interface) and play it more like a sample pad. Inversely, it’s possible to set the keyboard to hold one or more notes down and then clear the overlay off the grid (the held note will still light), leaving you free to impulsively experiment with different emitters to your heart’s content.

Below the Tempera’s four encoders are four screens, which, granted, does sound like a lot; I’ll say that upon first impression I was a little daunted by the idea of menu diving four ways, but in practice it doesn’t really work like that, and where it does it entails little navigation. In fact, the screens serve more often as simple displays for the functions of the four encoders than they do for menus; displaying settings, waveforms for audio files, encoder parameters and more. Every now and then navigating between the encoders, direction buttons and round ‘context switch’ button — whose raison d’être seems to be to pick up any pieces left behind by other parameters — could become awkward; for example on more than one occasion I found myself confused as to why an emitter wasn’t responding to my edits, only to discover I was editing the wrong one.

This said, a column of eight buttons down the right‑hand side allow for one‑push navigation to more or less all of its key screen pages and functions. From top to bottom these are for samples (including trimming and editing audio), emitters, keyboard settings, modulation (envelopes and LFOs), effects (filtering, chorus, delay and reverb), global settings, file directory and ‘custom macros’, which allows disparate parameters to be handily grouped in one place for quick access in performance.

The Tempera, then, is generally a screenless experience overall. Its grid of coloured cells delivers as clear a display of what’s happening as one could hope for and pretty much nothing in its technicolour lightshow is gratuitous. Visually the cells are incredibly responsive to what’s happening sonically, for instance fading in and out, and the strobe‑like scattering of colour around trigger points gives a transparent indication of what each emitter is actually doing across the Tempera’s grid, which is crucial since triggering different slices of audio can produce wildly different sonic results. It’s a smug feeling, using something so very pretty whose prettiness is in fact key to keeping abreast of what is going on.

Serious Fun

We’re now a decade on, I’m informed, from when the idea of a 2D cross‑sample instrument that would become the Tempera was first conceived. It makes sense; I can only imagine how dogged an iterative process its design must have entailed. It’s an alluring idea to have several samples working simultaneously across four granular engines with a capacitive touch interface; but keeping the workflow from becoming so finicky as to be unnavigable, while still retaining the detail and flexibility one would hope for from an instrument like this — and for its price — is another challenge entirely.

Nevertheless, while I’m sure future firmware updates will yield further functions and refinement, the result is one very impressive machine. It’s fun, but it’s serious fun: every multi‑coloured flash has a purpose, near enough every inch feels thought out. Needless to say, it’s also incredibly deep, accommodating a huge range of workflows. It rewards cavalier doodling as well as it does careful tweaking, and is certain to prove an asset for composition, sound design, performance and improvisation in equal measure, depending on your needs and workflow. As I said at the start of this review, I greatly respect Beetlecrab’s decision to hide the ball with their branding as they do, but it would be remiss of me not to say they deserve all the credit they can get for this fantastic little box.