For two decades, Haken Audio’s Continuum has stood apart: not a keyboard, not a conventional controller, but a continuous playing surface where the finger constantly shapes pitch, timbre and dynamics. The catch has always been that a full-size Continuum is long, heavy and expensive. With the Slim 21, shipping since 21 August 2026, Haken takes all three obstacles head-on: this is the most compact and affordable member of the family, at $1,799 / EUR 1,949.
A Continuum stripped to the essentials
The concept is untouched. The playing surface is neoprene, striped red and black to mark the semitones, and every finger is tracked individually. You do not press a key: you place, slide and push, and the instrument turns those three gestures into three control axes. The Slim 21 offers 21 semitones, a little under two octaves, a deliberately tight range that fits a 45 x 19 x 3 cm body weighing just 1.6 kg. It slips into a backpack, something no full-size Continuum ever did.
Three dimensions of playing, captured beyond MIDI
This is where the Slim 21 pulls away from a plain MPE controller. Under the neoprene, up to twelve Hall-effect sensors per finger sample the movement, digitised by 14-bit converters. In other words, the playing resolution goes well past the 128 steps of legacy 8-bit MIDI: vibrato, portamento and micro pressure changes gain a level of detail few expressive surfaces reach. The Slim 21 is of course MPE compatible, so it can drive any synth that speaks the protocol, much like the MPE-enabled discoDSP Corona 7 or the Audio Damage AD-202 with its microtuning.
EaganMatrix: one engine, several synthesis types
The Slim 21 is not just a controller: it carries the EaganMatrix engine, the very same one found in the larger Continuums. This modular synthesis matrix spans virtual analogue, additive and physical modelling, and is configured through the Haken editor for macOS and Windows. You can play the instrument on its own, with no computer or external module, or use it as a control surface into another engine. That matrix approach, wiring sources to destinations to draw a timbre, echoes the spirit of the architectures we break down in our FM synthesis explainer: a few building blocks, a lot of routing, a very wide sonic field.
| Specification | Haken Slim 21 |
|---|---|
| Playing surface | Continuous neoprene, per-finger tracking |
| Range | 21 semitones (nearly 2 octaves) |
| Sensors | Up to 12 Hall-effect sensors per finger, 14-bit converters |
| Sound engine | EaganMatrix (virtual analogue, additive, physical modelling) |
| Protocol | MPE compatible, macOS / Windows editor |
| Dimensions / weight | 45 x 19 x 3 cm / 1.6 kg |
| Price | $1,799 / EUR 1,949 |
Where the Slim 21 sits in the range
Haken already offers several formats: the full-size Continuum, the EaganMatrix Micro, the ContinuuMini, and the Slim 46 and 70. The Slim 21 takes the bottom of that ladder: less range, but the complete engine and the same surface. It is the most credible entry point the company has ever put out for anyone who wants a taste of three-dimensional playing without committing to a fixed studio instrument. At this price it goes up against high-end expressive controllers, yet none pairs this surface with this engine.
My take
I have always seen the Continuum as one of the rare electronic instruments that genuinely closes the gap between a player’s gesture and the resulting sound, in the way a good bow or a reed does. A keyboard, handy as it is, chops the sonic continuum into stair steps; here you get the slope back. The Slim 21’s bet is to make that expressivity portable and to break the price barrier without touching the engine. One thing is obvious: two octaves means accepting octave shifts and rethinking your hand position. That is not a flaw, it is an instrument to learn, and that is exactly what makes it worthwhile to me.
The Slim 21 is available now at $1,799 / EUR 1,949. An official demo is embedded below.
