When MPE synth roundups get written, the same handful of names tend to show up: wavetable engines from the big-name developers, physical modeling synths built specifically for expressive controllers, and the usual suspects from Arturia, u-he, and Native Instruments. Madrona Labs rarely makes that list, which is a shame, because its synthesizer Sumu is one of the more unusual and capable MPE instruments on the market.
What Sumu Actually Does
Sumu breaks from familiar synthesis territory by combining additive resynthesis, FM, and vector-field spatialization in a single instrument. Rather than the typical oscillator-filter-envelope signal path, Sumu is built around a collection of ten modules connected through a unique multi-channel patcher, letting sound designers route audio and modulation in ways that don't map cleanly onto conventional synth architecture. The result is a synth capable of textures that feel genuinely different from what a Serum, Pigments, or Massive preset library tends to produce — shimmering, spatially complex tones that respond in unusual ways to modulation.
That unpredictability is exactly what makes it interesting for MPE players. Expressive controllers reward instruments that respond richly to continuous, per-note modulation rather than just layering static timbral changes on top of a note. Sumu's vector-field spatialization engine, in particular, gives per-note pressure and slide data somewhere genuinely interesting to go, rather than just riding a filter cutoff or amplitude parameter the way many simpler synths do.
The MPE Implementation
Sumu's MPE support arrived via a free update for existing owners and includes the details that matter for serious expressive performers rather than a bolt-on afterthought. Users can switch between standard MIDI and MPE input modes, set the per-note pitch bend range to match their controller (with presets at 0, 12, 24, 48, and 96 semitones), and rely on Sumu's modulation routing automatically remapping itself between modes — Timbre/Y replaces Classic Modulation and MPE Pressure/Z replaces Classic Pressure, with the same routing options preserved in both modes. That means patches largely translate cleanly whether you're playing on a standard keyboard or an MPE controller like a Seaboard, LinnStrument, or Osmose.
The update also reduced input latency for gate and pitch data through the patcher, a detail that matters more than it might sound for anyone playing fast, expressive lines on a touch-sensitive surface — latency in the pitch path is one of the fastest ways to make an MPE performance feel disconnected from the controller.
Where It Fits in a Rig
Sumu isn't trying to be a general-purpose workhorse synth, and it's not the instrument to reach for if you want familiar analog-modeled bass or pad sounds. It's better suited as a specialist tool: a second or third MPE instrument in a rig, reserved for textures, evolving pads, and sound-design work where its additive-and-spatialization approach can actually be heard. Paired with a controller that offers continuous per-note pressure and slide — an Expressive E Osmose, a ROLI Seaboard, or a LinnStrument — it can produce sounds that are difficult to get anywhere else.
Sumu is priced at $179 for new customers, with the MPE-supporting update free for existing owners. For MPE musicians who feel like they've already exhausted the usual synth suspects and are looking for an engine that genuinely rewards deep modulation exploration, it's worth downloading the demo and spending an afternoon with the patcher before writing it off as niche.