Haken Audio Slim 21: The Most Accessible Continuum Yet Arrives at $1,799

For nearly three decades, the Haken Continuum Fingerboard has occupied a rarefied position in the world of expressive instruments — revered by composers, sound designers, and MPE enthusiasts alike, but constrained by its price and size from reaching a broader audience. That's starting to change. Unveiled earlier this spring and shown publicly at Superbooth 2026, the Haken Audio Slim 21 is the most compact and affordable Continuum ever made, priced at $1,799.

What Is the Continuum?

For those new to the instrument, the Continuum Fingerboard is a continuous playing surface — no keys, no frets, no discrete buttons. Your fingers interact directly with a soft, seamless neoprene surface, and the instrument tracks their position in three dimensions simultaneously: left-right (pitch), up-down (timbre/pressure), and pressure depth (loudness). Each finger is tracked independently, making it one of the most expressive instruments in existence.

Unlike a standard keyboard, the Continuum has no "note slots." Pitch is continuous, so you can glide between notes, perform microtonal passages, or apply precise vibrato at will — all with the same physical gesture.

The Slim 21 Form Factor

Previous Continuum models — the Half Size and Full Size — were wide, desk-occupying instruments. The Slim 21 changes that equation dramatically. At just 45 × 19 × 3 cm and 1.6 kg, it fits in a backpack and sits comfortably on a keyboard stand or desk without dominating the workspace.

The "21" in the name refers to its 21-half-step range — just under two octaves. That's a deliberate design trade-off. Haken Audio reasoned that many Continuum players work in limited pitch ranges anyway, using the instrument for expressive melodic lines and timbral exploration rather than wide-range classical repertoire. In that context, a compact, ultraportable 2-octave surface is genuinely practical.

Full EaganMatrix Engine Inside

Despite its reduced footprint, the Slim 21 makes no compromises on the sound engine. It runs the complete EaganMatrix synthesis system — the same engine found in the full-size Continuum and the Osmose synthesizer (which licenses it from Haken Audio). EaganMatrix supports multiple synthesis paradigms simultaneously: virtual analog, additive synthesis, physical modeling, and FM, all in a complex modular patching environment designed to respond naturally to the Continuum's three-dimensional input.

This matters because the EaganMatrix is purpose-built for continuous, high-resolution expression. Standard synth engines often struggle with the kind of dense, rapidly-changing expression data that a Continuum generates. The EaganMatrix handles it natively, producing results that feel immediate and musical rather than lagged or quantized.

Sensor Technology

Under the neoprene surface, the Slim 21 uses up to 12 independent hall-effect sensors per finger, with ultra-high-speed analog-to-digital conversion. This gives the tracking an extremely fine resolution — far beyond what standard MIDI pitch bend or CC can express. The output is sent over MPE (and the Continuum's own extended protocol, CVC) to ensure full compatibility with modern DAWs and MPE-capable hosts.

The Haken Editor software (available for macOS and Windows) provides a full visual interface for crafting patches on the EaganMatrix, saving presets, and configuring the surface sensitivity to your playing technique.

Who Is It For?

The Slim 21 occupies a distinct space in the MPE ecosystem. It's not a controller in the traditional sense — it has a full synth engine built in. But it also works as a high-resolution MPE input device for external instruments. For composers who want the most expressive possible input device combined with an instrument capable of sounds nothing else can produce, the Slim 21 is the most accessible entry point into the Continuum world.

At $1,799, it remains a significant investment. But compared to the full-size Continuum (which starts at over $5,000), it's a genuine step change in accessibility. For players curious about what continuous-surface performance feels like — without committing to a large instrument footprint — the Slim 21 is the logical starting point.