Mike Martin spent years at Casio, TC Electronic and Yamaha before returning to the brand he started with, KeySolutions Sounds. His first synthesizer under that name arrived on September 1st: Traveler, a cinematic hybrid plugin for macOS and Windows built around motion and an immersive stereo architecture.

It is, on paper, an expressive instrument. It supports mono and polyphonic aftertouch, polyphonic glide, separate up and down pitch-bend settings, and full MIDI CC learn. What it does not yet support is MPE — a detail worth unpacking, because the gap between those two feature lists is where a lot of confusion lives.

What Traveler actually does

The engine is a three-oscillator hybrid. Oscillator 1 is conventional; Oscillator 2 runs a seven-voice unison super stack with detune and stereo spread; Oscillator 3 is wavetable-based with 85 tables and support for importing your own. Oscillator sync plus linear and exponential FM are available, and a Vintage parameter adds oscillator drift.

Those sources feed a dual/stereo filter section with ladder models at 6, 12, 18 and 24 dB/octave plus NJM2069-style (Korg DW-8000) 12 and 24 dB models, an independent high-pass with cutoff tracking, and pre-filter drive. The stereo behaviour is the distinguishing trick: left/right frequency spacing, a per-voice "Spread" parameter that alternates filter offset per note, per-oscillator panning and per-key alternate panning.

Modulation runs deep — three polyphonic LFOs with 21 shapes, three envelopes with switchable ADSR or ADBSSR stages and editable curves, and a 21-slot matrix with 92 destinations. A dual 16-step sequencer and a 20-mode arpeggiator handle rhythmic motion. Over 400 presets come from a strong roster of sound designers including Venus Theory, David Helpling, Scott McAuley and John "Skippy" Lehmkuhl.

Traveler is available now at an introductory $99, down from $149, through September 30, 2026, and it bundles the KeyTIME and KeySPACE effects plugins (normally $49 each) at no extra charge. A 14-day demo is offered, and it runs standalone plus VST3, AU and AAX.

Poly aftertouch is not MPE

Here's the distinction that matters if you play an expressive controller.

Polyphonic aftertouch sends a separate pressure value for each held key, on a single MIDI channel, using MIDI's poly key pressure message. That's genuinely per-note — a synth that supports it lets you press harder on one note of a chord and hear only that note respond. Controllers like the Fender Motion series, Arturia's PolyBrute 12 and various Sequential keyboards send it.

MPE solves a broader problem. By spreading notes across multiple MIDI channels, it gives each note its own pitch bend, its own CC74 slide value and its own pressure, all continuously. Pressure is only one of three dimensions; per-note pitch is the one that makes glides, vibrato and microtonal bends work independently on each finger.

So Traveler will already respond usefully to a poly-AT keyboard, and its per-voice Spread and panning features suggest an engine that was designed with per-note variation in mind. But on a Seaboard, LinnStrument, Osmose or Continuum, the pitch and slide dimensions have nowhere to go. Bending one note in a chord will bend all of them.

Why this keeps happening

Adding MPE to an existing synth architecture isn't a checkbox. It means reworking voice allocation so channels map cleanly to voices, deciding how per-note pitch bend interacts with glide and unison stacks, handling channel rotation, and making sure every modulation destination can accept a per-voice source. For a plugin with a 21-slot matrix and 92 destinations, that's real engineering.

The encouraging part is that the underlying architecture here — polyphonic LFOs, per-voice envelopes, per-note filter offsets — is exactly the kind of design that makes MPE support tractable later. Several instruments have added it this way in 2026, arriving as a free point update months after launch.

For now, if you're shopping specifically for MPE, treat "polyphonic aftertouch" in a feature list as a promising signal rather than a synonym. And if you're buying Traveler for its cinematic presets and stereo motion — which look like the real selling points — the intro price runs to the end of September either way.

More information: KeySolutions Sounds · Announcement coverage at Synth Anatomy