Hex MIDI v0.8.100
Geometric Harmony & Microtonal Synthesis

The Modern Isomorphic Keyboard

Hex MIDI replaces the traditional asymmetrical piano with mathematically invariant hexagonal grids. Learn a chord or scale once, and play it identically across all 12 keys and microtonal temperaments without changing your finger shape.

12 Isomorphic Keyboard Layouts & Custom Engine

Every layout is calculated in real time using axiomatic 2D coordinate vectors. Select an instrument family tab to view its layouts:

Wicki-Hayden

Hexagonal • Pointy-Top

The premier isomorphic concertina layout. Pairs whole-tones horizontally with pure fifths and fourths along the diagonals. Octaves stack directly vertically for natural two-handed harmony.

Best for: Jazz voicings, rapid chord transposition, concertina players.

Jankó Classic

Hexagonal • Paul von Jankó (1882)

Historical alternating whole-tone keyboard where any musical scale uses identical physical spacing regardless of key signature. Enables tenths and twelfths with a single hand span.

Best for: Classical pianists, wide-interval reach, symmetric fingering.

Jankó Vertical

Hexagonal • Vertical Octaves

A modernized Jankó variant maintaining horizontal whole-tone parity while locking vertical columns strictly to pure octaves for streamlined multi-octave arpeggios.

Best for: Basslines, electronic leads, arpeggiated synth runs.

Harmonic Table

Hexagonal • Euler Tonnetz (1739)

Based on Leonhard Euler's 1739 Speculum Musicae. Minor thirds, major thirds, and pure fifths converge into triangular triads. Major and minor chords form intuitive 3-key geometric triangles.

Best for: Film scoring, modal jazz, neo-Riemannian music theory.

Bosanquet-Wilson

Hexagonal • Generalized Keyboard

Invented by R.H.M. Bosanquet and refined by Erv Wilson. The definitive generalized keyboard for exploring higher-order EDO temperaments (such as 31, 41, and 53-EDO) with consistent fingering.

Best for: Microtonal research, xenharmonic theory, 31/53-EDO.

Accordion C-System

Accordion • C-Griff

Standard European C-Griff button accordion layout. Keys progress by semitones along the diagonal and minor thirds horizontally, packing over 4 octaves into a compact ergonomic surface.

Best for: Classical accordionists, tango, folk, fast virtuosic runs.

Accordion B-System

Accordion • B-Griff / Bayan

The mirrored counterpart to C-Griff, widely used in Eastern European and Russian Bayan playing. Inverts the diagonal progression for enhanced melodic comfort in traditional repertoires.

Best for: Bayan accordionists, Eastern European folk, conservatory pieces.

Harpejji

Strings • Two-Handed Tapping

Inspired by the physical Harpejji acoustic-electric instrument. Combines a horizontal whole-tone stepping arrangement with vertical fretted strings for intuitive two-handed chord tapping.

Best for: Keyboardists wanting a string-like feel, two-handed tapping.

Diminished Harmonica

Wind & Free-Reed • Diminished Symmetry

Emulates the interval distribution of chromatic and diminished harmonica instruments. Every row mirrors the same 4-note diminished symmetry, simplifying complex bop improvisations.

Best for: Harmonica players, bebop lines, diminished chord substitutions.

Major Thirds

Hexagonal • Augmented Symmetry

Spaces keys by major thirds horizontally and semitones along the axis. Generates immediate access to augmented triad cycles and Coltrane changes with uniform fingerings.

Best for: Coltrane matrix substitutions, symmetrical harmony, modern jazz.

Perfect Fourths

Strings • Guitar & Bass

Maps a standard stringed instrument fretboard tuned in straight perfect fourths (E-A-D-G-C-F). Eliminates the B-string shift irregularity of standard guitars for 100% invariant box shapes.

Best for: Guitarists, bassists, string players transitioning to MIDI.

All Fifths

Strings • Quintal Grid

Maps orchestral string instruments tuned in pure fifths (C-G-D-A-E). Gives violinists, violists, and cellists immediate muscle-memory transfer to polyphonic synthesis.

Best for: Orchestral string players, wide intervallic sweeps.

Custom Designer

PRO • Fully Configurable

Design your own hexagonal or square isomorphic keyboard from scratch. Set custom interval shifts, base anchors, and export/import presets via portable JSON files.

Best for: Acoustic researchers, instrument inventors, experimentalists.
View all 13 layouts in compact comparison table
Layout Family Geometry / Type Strengths & Applications
Wicki-Hayden Hexagonal Pointy-Top Hex Jazz voicings, whole-tone steps, vertical pure octaves
Jankó Classic Hexagonal Paul von Jankó (1882) Classical piano fingerings, large interval reach
Jankó Vertical Hexagonal Vertical Octaves Arpeggiated synth leads, multi-octave sweeps
Harmonic Table Hexagonal Euler Tonnetz (1739) Triangular triads, neo-Riemannian theory, film scoring
Bosanquet-Wilson Hexagonal Generalized Keyboard Microtonal xenharmonic theory, 31/53-EDO
Accordion C-System Accordion & Wind European C-Griff Classical accordion, tango, folk, virtuosic runs
Accordion B-System Accordion & Wind Russian Bayan / B-Griff Bayan players, inverted diagonal progression
Harpejji Fretboard & Strings Tapping Grid Two-handed string tapping, whole-tone fret matrix
Diminished Harmonica Accordion & Wind Diminished Matrix Bebop lines, chromatic reed symmetry, minor thirds
Major Thirds Hexagonal Augmented Matrix Coltrane matrix cycles, augmented triad symmetry
Perfect Fourths Fretboard & Strings Fretboard Grid All-fourths guitar & bass fretboard, invariant box patterns
All Fifths Fretboard & Strings Quintal Grid Violin, viola & cello quintal fingerboard transfer
Custom Designer Custom Engine PRO Configurable Fully customizable generator vectors with JSON export/import

40+ Microtonal Scales & Historical Temperament Engine

Break beyond 12-tone equal temperament. Hex MIDI calculates real-time acoustic frequencies and delivers per-note pitch bends via MPE. Select a tuning family:

12-EDO Standard
100.0¢ steps • Western equal temperament baseline
19-EDO Meantone
63.16¢ steps • Superb 1/3-comma meantone & pure minor 3rds
22-EDO Porcupine
54.55¢ steps • Septimal superpyth harmony (7-limit chords)
24-EDO Quarter-Tone
50.0¢ steps • Arabic maqams & 20th-century spectralism
31-EDO Huygens-Fokker
38.71¢ steps • Near-pure 5:4 thirds (387¢) & 7:4 harmonic 7ths
41-EDO Miracle
29.27¢ steps • Ultra-accurate fifths (702.4¢) & septimal triads
53-EDO Mercator
22.64¢ steps • Pythagorean comma division & Turkish Makam
72-EDO Sixth-Tone
16.67¢ steps • Byzantine liturgical & 11-limit micro-intervals
Sub-12 EDOs 3 to 11
Slendro (5-EDO), Whole-Tone (6-EDO), Thai Gong (7-EDO)
Extended EDOs 15 to 118
Carlos 15-EDO, Safi al-Din 17-EDO, Sauveur 43, 88, 118-EDO
7-Limit Just Intonation Pure Ratios
Acoustically pure 3/2, 5/4, 7/4, 9/8 intervals with zero beats
1/4-Comma Meantone Aron 1523
8 mathematically pure 5:4 major thirds (386.3¢) & sweet Baroque cadences
Pythagorean 12-Tone 3-Limit
Built on pure 3:2 fifths; ancient Greek & Medieval sacred music
Werckmeister III 1691 Well-Temperament
4 narrowed fifths allowing all 24 keys of J.S. Bach to sound expressive
Kirnberger III & Vallotti Baroque
Pure C-E major third + 1/6-comma equalized diatonic cycle
Harry Partch 43-Tone 11-Limit JI
Iconic 43-tone acoustic Tonality Diamond for American microtonal pioneer music
Indian 22 Shruti Natya Shastra
Ancient Indian 5-limit shrutis: Kṣobhinī, Tīvrā, Kumudvatī, Rañjanī
Arabic Maqam Suite 24-EDO Quarter-Tone
Authentic Maqam Rast (Sikah & Ouj quarter-tones), Bayati, and Hijaz
Turkish Makam Rast 53-Holdrian Comma
Classic Turkish 9-comma Segâh, Dügâh, Çargâh, and Gerdaniye steps
Byzantine Liturgical 72-Moria
Chrysanthine 72-moria liturgical chant division (12-9-9-12-12-9-9)
Indonesian Gamelan Pelog & Slendro
Javanese 7-tone unequal Pelog and 5-tone Slendro distribution
Bohlen-Pierce 13-EDT (3:1 Tritave)
Divides the 3:1 tritave (1902¢) into 13 equal steps using odd harmonic ratios (3:5:7:9)
Wendy Carlos Alpha 78.0¢ Steps
Non-octave scale dividing intervals for near-pure 3:2, 5:4, and 7:4 chords
Wendy Carlos Beta 63.8¢ Steps
19-tone non-octave scale providing pure fifths, major thirds, and 11:8 fourths
Wendy Carlos Gamma & Harmonic 35.1¢ Steps
Pure major and minor thirds with no fifths, plus proportional harmonic series
Mosh MOS 10-EDO 7-Tone
3L 4s pattern with characteristic 360¢ neutral thirds
Porcupine MOS 22-EDO 7-Tone
6L 1s pattern with distinctive septimal minor thirds
Miracle MOS 41-EDO 7-Tone
6L 1s pattern with ultra-accurate 5-limit and 7-limit harmony
Scala (.scl / .kbm) Engine PRO
Import any of the 5,000+ scales from the Huygens-Fokker archive or export your own

Studio Audio & Expressive MIDI Routing

Hex MIDI functions as both an expressive standalone instrument and a low-latency MIDI controller for external gear:

SpessaSynth SF3 Soundfont Engine

High-fidelity 16-bit soundfont synthesis supporting compressed SF3 and uncompressed SF2 soundbanks. Includes stereo chorus, reverberation, equalizer, and real-time envelope filtering.

MPE & Continuous Pitch Bend

Dynamic 15-channel MPE voice allocation. Each note receives its own microtonal pitch-bend stream, enabling polyphonic microtonal playback on standard MPE-compatible software.

Class-Compliant USB & Bluetooth MIDI

Plug directly into Mac, PC, iOS, or Android via USB-C or pair wirelessly via low-latency Bluetooth LE MIDI. Controls external synths and DAWs like Ableton Live, Logic Pro, and Bitwig.

Timeline Minimap & Pattern Sequencer

Interactive zoomable overview bar showing active viewport bounds, real-time playhead seekbars, and a multi-track pattern sequencer for loop recording and MIDI file export.

Hex MIDI Free vs PRO Feature Matrix

We are dedicated to keeping isomorphic music theory accessible to all, with an optional Pro upgrade for research and studio power users:

Feature Free Tier Hex MIDI PRO
All 12 Built-in Isomorphic Layouts (Wicki, Janko, Tonnetz, Accordion, Harpejji) Full Access Full Access
Custom Axiomatic Layout Designer (Create, Save & Export) — Unlimited
Core Microtonal Scales (12-EDO, 19-EDO, 24-EDO) Included Included
Full 40+ Scale Catalog (22, 31, 41, 53-EDO, Bohlen-Pierce, Partch, Makams) — Unlimited
Custom Scala (.scl / .kbm) Import & Export — Unlimited
USB & Bluetooth LE MIDI Input/Output with MPE Pitch Bends Included Included
SpessaSynth SF3 Soundfont Engine & Custom Soundbank Loading Included Custom Banks
MIDI Recording, Multi-Take Playback & .MID File Export Included Included
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Frequently Asked Questions

Common questions about isomorphic keyboards, microtonal tunings, and Hex MIDI:

What is an isomorphic keyboard and how does it differ from a traditional piano?

On a traditional piano, the physical distance between intervals changes depending on which key you start on (for example, C major uses all white keys, while F# major uses mostly black keys). On an isomorphic keyboard (such as Wicki-Hayden or Jankó), geometric distance is invariant. Any chord shape (major, minor, diminished, or ninth) keeps the exact same hand shape anywhere on the board.

How do I connect Hex MIDI to Ableton Live, Logic Pro, or hardware synthesizers?

On mobile and web, connect a USB cable or pair via Bluetooth MIDI in your system settings. In your DAW, enable Hex MIDI as an active MIDI input track. All note-on, velocity, aftertouch, and MPE pitch bend data stream directly into your virtual instruments with sub-millisecond response.

What microtonal tuning should I try first if I'm new to xenharmonics?

Start with 19-EDO or 31-EDO. Both belong to the meantone temperament family, meaning standard chords sound familiar but with significantly purer thirds and sweeter resolutions than standard 12-tone equal temperament. For middle-eastern quarter tones, try 24-EDO or Arabic Maqam Rast.

Where are my recorded MIDI takes and custom presets stored?

Hex MIDI is 100% local-first. Your exported MIDI files, custom presets, and soundbanks are saved directly to your device storage (inside the Documents folder on iOS and Android, or IndexedDB in the browser). No musical data is ever sent to external cloud servers.

Ready to Play in Geometric Harmony?

Launch Hex MIDI instantly in your web browser with zero installation, or connect your USB/Bluetooth MIDI controller and custom soundfonts.

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