For nearly two decades, the Haken Continuum has been the instrument MPE players point to when they want to explain just how expressive electronic performance can get. Its neoprene-covered fingerboard tracks every finger independently, translating the smallest shifts in pressure, position, and glide into sound with a resolution that rivals acoustic instruments. The catch has always been size and price. That changes, at least partially, with the introduction of the Slim 21, a more compact member of the Continuum Fingerboard family.
A smaller footprint, the same engine
The Slim 21 measures roughly 45 x 19 x 3 cm and weighs about 1.6 kg, a fraction of the full-size Continuum's footprint. What hasn't shrunk is the instrument's core: the Slim 21 runs the same EaganMatrix Sound Engine found in Haken's flagship models, and it uses the same per-finger tracking technology, with up to 12 independent Hall-effect sensors reading each finger's position. A single note played on the instrument generates hundreds of thousands of sensor samples, which is what gives the Continuum family its reputation for extreme sensitivity compared to a conventional keybed.
The trade-off for the smaller size is range: the Slim 21 covers 21 notes rather than the multi-octave span of the larger Continuum models. For players who use the instrument primarily for lead lines, solos, or expressive layering rather than full keyboard-style performance, that narrower range is unlikely to be a dealbreaker, and it makes the instrument realistic to fit into a touring rig or a smaller studio desk.
Why this matters for MPE
The Continuum has always been a reference point in MPE circles because it predates the standard itself and helped shape the thinking behind per-note expression. A more portable version lowers the practical barrier to owning one, even if the $1,799 USD price tag keeps it firmly in the "serious instrument" category rather than an impulse buy. Composer Josh Madoff published an in-depth walkthrough of the instrument shortly after launch, giving prospective buyers a clearer sense of how the Slim 21 feels in practice compared to its larger siblings.
It's worth placing the Slim 21 next to the rest of the current MPE controller field. The ROLI Seaboard Rise 2 uses a soft keywave surface aimed at keyboardists who want a familiar layout with added expression. The Expressive E Osmose pairs a semi-weighted, pressure-sensitive keybed with its own synth engine. LinnStrument from Roger Linn favors a grid layout that excels at wide glissando-style pitch bends. The Continuum family, including now the Slim 21, remains the option most associated with continuous, violin-like control over pitch and timbre, at the cost of a steeper learning curve for players coming from a traditional keyboard background.
Where it fits in a rig
Because the Slim 21 speaks standard MPE, it slots into the same workflow as any other MPE controller: route it into an MPE-aware instrument inside a DAW like Ableton Live, Bitwig Studio, or Logic Pro, and per-note pitch, pressure, and timbre data comes through independently for each note played. That makes it just as useful for sound designers building expressive orchestral or synth patches as it is for solo performers looking for a compact, take-anywhere expressive instrument.
Haken Audio has not announced a specific number of orders or shipping timelines beyond general availability, but the Slim 21 is listed as available now directly through Haken Audio's website. For anyone who has wanted to try Continuum-style playing without committing to the full-size instrument's space and cost, the Slim 21 is the most accessible entry point the company has offered so far.