A name that matters to anyone in the MPE world is back with a new instrument. Geert Bevin, the developer who worked on the Eigenharp, the Roger Linn LinnStrument and Moog Music's multitouch iOS apps, has released Glinster, an MPE controller and instrument for Apple Vision Pro, iPhone and iPad. According to Synthtopia's report, Bevin also authored the original draft of the Multidimensional Polyphonic Expression specification, the work that led to what we now call MPE.
A layout that follows your hand
Glinster does not give you a fixed keyboard or grid. Instead, it measures the shape and reach of your hand and builds the playing surface around it. On Apple Vision Pro you play in the air with bare hands, using spatial hand tracking. On iPhone and iPad you rest your hand anywhere on the glass and the notes appear under your fingers, positioned according to your measured finger spacing.
That approach is a refreshing answer to a familiar problem. Many players find that a standard layout fits some hands better than others, and touchscreens in particular have always struggled with the lack of physical landmarks. Letting the instrument adapt to the player, rather than the other way around, is a sensible idea for a device with no keys to find.
Built-in sounds and musical controls
Glinster is also a self-contained instrument, so you can play it without a DAW. It ships with five sound presets, named Aether, Ember, Fathom, Rime and Pillar, and exposes controls for Room, Shimmer, Glide, Response, Cutoff and Resonance. There are 16 scales, including the seven modes, blues, whole tone and double harmonic, along with 12 selectable roots and a reference pitch adjustable from 432 to 446 Hz. An octave setting shifts the instrument two octaves in either direction.
Takes can be recorded as lossless 32-bit float WAV files, and playback happens inside the app while the instrument stays live, which makes it handy for quick sketching.
The MPE side
For MPE users, the MIDI implementation is where Glinster gets interesting. Each note is sent on its own channel, and you can choose how many member channels to use, or fall back to single-channel output if your destination is not MPE-aware. A "Send MCM" button transmits the MPE configuration message, which helps when a receiving synth needs to be told it is working in MPE mode.
Volume and brightness can be mapped to channel pressure, CC 7, CC 11, CC 74 or CC 1, and the pitch bend range can be set to 2, 12, 24, 48 or 96 semitones. If you have ever fought a pitch bend range mismatch between a controller and a plugin, you will appreciate having this many options in one place.
Connectivity covers most modern setups: a virtual MIDI source, direct output to any app's MIDI port, Bluetooth LE MIDI in both directions, and Apple network MIDI sessions. That means you can send expressive data to a synth running on the same iPad, a Mac across the room, or a hardware instrument via a wireless MIDI adapter.
Price and availability
Glinster is available now for Vision Pro, iPhone and iPad at $9.99, and the App Store purchase includes AUv3 functionality. Synthtopia's article does not break the price down by platform, so check the App Store listing before you buy. You can find more information on the developer's Glinster page.
Why it matters for MPE players
Spatial computing is still a niche for music, but Glinster is a useful data point. It shows that MPE is not tied to a particular hardware shape: the same per-note pitch, pressure and timbre model works whether your fingers touch glass or move through the air. It also lowers the cost of entry, since a ten-dollar app can give a curious player a real taste of per-note expression before they commit to a dedicated controller.
If you already own an iPad, it is worth trying alongside other mobile options. Our guide to using MPE on iPad with AUv3 hosts covers the host side of the equation, while our overview of MPE slide and CC74 mapping explains what the brightness mapping options in Glinster actually do to your sound.
The bottom line: Glinster is a thoughtful, low-priced entry from someone who has shaped the MPE ecosystem from the start. Whether you play it with a Vision Pro headset or just a phone, it is a good reminder that expressive playing can happen anywhere your hands do.