ChordGrid: MIDI Instrument

ChordGrid turns a phone or tablet into a MIDI chord instrument. It sends note data to hardware synths, samplers and DAWs over USB. It also has a voice of its own, so it plays through the device's own speaker with nothing attached: pick it up, press a chord, hear it.

Two instruments share one engine, one key and one set of controls. Switch between them from the top of the screen.

THE GRID
Set a key and a mode and the app fills a seven-row grid, one row per scale degree, with a chord palette for each: triads, sixths and sevenths, then ninths, elevenths and thirteenths, suspensions, added tones, slash voicings and pedals — and a family that leaves the key altogether, with secondary dominants, tritone substitutes and modal interchange. Tap a tile and the chord plays.

FLOWER MODE
The other way round. A bank of chord types down the left, a labelled keyboard of the key's own notes across the bottom: hold maj7, tap E, and an E major seventh sounds. The same shape wherever you put it. LATCH TYPE keeps a chord type armed when you let go, for one-handed play; off, it holds only while pressed. MORE CHARACTER turns every chord type into its richer form at once — major becomes a major ninth, the seventh becomes a thirteenth.

With nothing held, the keyboard still plays: every key gives you the chord that belongs to that degree of your key. Nothing you play is out of key unless you choose a chord that is.

THE FADER
A fader down the right-hand side sweeps continuously through the inversions and voicings of the chord you are holding, one voice at a time, so the harmony flows rather than jumps. Octave buttons at each end shift its whole range, for a patch that sits too high or too low.

NO GAP BETWEEN CHORDS
Land the next chord before you lift the last one and it takes over, holding the notes the two have in common. Lift the new one while the old is still down and it goes back to the old one. A level bar beside the fader sets how hard the chords play; in Flower mode, where you land on a key does it instead.

SOUND WITH NOTHING PLUGGED IN
A built-in synth voice, a filtered sawtooth, sits in the device list beside your interfaces, and is chosen for you when nothing is connected. Plug an interface in and the app moves to it unasked; unplug it and the sound returns to the device. Android will also offer to open ChordGrid whenever an interface is connected.

BUILT FOR STAGE
Landscape, dark, no pop-ups. LATCH holds a chord with no finger on it. PANIC silences everything. The screen stays awake. The play surface cannot be scrolled by accident, so a chord never sounds while you are reaching for one — the columns move from a rail along the top instead. Plug the same interface in twice and it reconnects to it.

YOUR OWN LAYOUT
Chord types are grouped into banks. Reorder them, switch any of them off to make the grid narrower, or build a bank of your own from whichever chord types you actually reach for.

FREE, AND PAID
The core chords — triads, sixths and sevenths across thirteen scales, and the five everyday chord types in Flower mode — are free and always will be. One payment unlocks the rest in both instruments: extensions, suspensions, added tones, slash voicings, pedals, and the chords outside the key. Not a subscription.

SET UP TO TASTE
Thirteen modes, from the familiar seven through the modes of harmonic and melodic minor. Voice count and voicing shape. Bass behaviour, register memory and voice leading. Fader range. Strum spread, direction, curve and humanisation. MIDI channel and transpose. Chord spelling.

PRIVACY
No account, no analytics, no crash reporting, no tracking and no advertising. ChordGrid uses the network for exactly one thing: letting Google Play confirm a purchase. Nothing you play is recorded and nothing about you is collected.

REQUIREMENTS
Android 7.0 or later, landscape. The built-in voice needs no hardware. For external gear: USB host support and a USB MIDI interface or class-compliant instrument.