Hex MIDI: Isomorphic Keyboard
Microtonal & Xenharmonic Synth
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Hex MIDI is an isomorphic MIDI controller and microtonal synthesizer. Instead of the standard piano keyboard, notes are arranged in geometric hexagonal grids - meaning chord shapes, scales, and intervals remain identical across every key.
Whether you want to play alternative keyboards like the Wicki-Hayden or Jankó, compose in 19-EDO / 31-EDO microtonal tunings, or control your DAW over MIDI and MPE, Hex MIDI gives you the tools to explore harmony through geometry.
Built-In Keyboard Layouts:
• Wicki-Hayden – Classic concertina layout with fifths/fourths diagonals and octave columns.
• Jankó (Classic & Vertical) – Whole-tone rows with uniform chord fingerings.
• Harmonic Table – Euler's Tonnetz grid: major/minor third diagonals with vertical fifths for visual chord building.
• Bosanquet-Wilson (Maupin) – Generalized flat-top hex layout built for microtonal navigation.
• Harpejji – Whole-tone string layout with semitone vertical progression.
• Chromatic Button Accordion – Authentic C-System and B-System (Bayan) layouts.
• Fourths & Fifths – String instrument tunings for guitarists, bassists, and violinists.
• Major Thirds & Diminished Harmonica – Symmetrical grid layouts.
• Custom Layout Editor – Build and save your own hexagonal or rectangular grids.
Microtonal & Tuning Engine:
• EDO Presets: 19-EDO, 22-EDO (Shruti), 24-EDO (Quarter-tone / Maqam), 31-EDO (Meantone), 41-EDO, 53-EDO, and sub-12 tunings (5-EDO Slendro, 7-EDO, 10-EDO).
• Scale Formats: Bohlen-Pierce (13-EDT), Just Intonation, and custom scale generation.
• Scala Support: Import standard .scl tuning files and .kbm keyboard mappings.
• Visual Color Modes: 5ths spiral color coding, Tonnetz harmonic spectrum, and minimal two-tone palettes.
• Note Labels: Display note names with arrow accidentals, Solfège, interval numbers, or exact Hz.
MIDI & Expressive Performance:
• MIDI I/O: Connect via USB MIDI to hardware synthesizers, external keyboards, and DAWs (Ableton, Logic, Reaper, Bitwig).
• MPE & Vibrato: Per-note microtonal pitch-bend routing and touch vibrato.
• MTS Support: Real-time MIDI Tuning Standard SysEx transmission for compatible synths.
• Touch Control Pads: Integrated dual X/Y pads for assignable pitch, modulation, and CC filters.
• Built-In Sound Engine: High-fidelity soundfont player with instant response.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
- Custom instrument group colors with an interactive color wheel.
- Looping Arpeggiator & Strum: Create rhythmic sequences with a looping arpeggiator and dynamic strumming styles.
- Chord Progressions & Voicings: Play guided chord progressions, rich jazz voicings, and explore the Circle of Fifths.
- Customize accidental notation with sharp #, flat b.
- Interactive Training Mode: Learn songs, chords, and scales with guided interactive practice.
- 15 Languages & Custom Themes.
The developer, Trung Dung Hoang, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Contact Info
- Identifiers
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Purchases
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Trung Dung Hoang
- Size
- 65.5 MB
- Category
- Music
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPad
Requires iPadOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Contains
Advertising
- In-App Purchases
Yes
- Hex MIDI Pro $12.99
- Copyright
- © 2026 Zung Studio