Overview

The Tightening is a desktop app for exploring harmony on a MIDI keyboard. It gives you three modes, accessible as tabs in the sidebar, all sharing a single Circle of Fifths:

  • Jam mode — play freely and watch your chord progressions build as a live graph, with MIDI detection naming each chord as you hold it.
  • Walk mode — pick two chords, let the app find the harmonic path between them across the circle of fifths, then play through it step by step.
  • Replay mode — load a recording folder and play it back: audio and MIDI run in sync, driving the circle just as it looked when you recorded.

All three modes centre on the Circle of Fifths — a 36-node graph of major, minor, and diminished chords connected by 11 harmonic relationships (fifths, diatonic moves, borrowed chords, chromatic mediants, and more).

Getting started

Download the latest release and run the installer. Windows will show a SmartScreen warning on first launch — click More info → Run anyway. The app is not yet code-signed.

Connect a MIDI keyboard before launching. The status indicator in the top-right corner shows the connection state. If nothing shows up, check your USB connection and relaunch.

Use the sidebar to jump to any topic. If you’re new, start with Walk Mode — it’s the fastest way to understand how the graph works. Once you’ve played a take you like, Replay Mode shows you how to capture and play it back.