Circle of Fifths MIDI Tool

🎵 Interactive Music Theory The Circle of Fifths is one of the most important diagrams in music theory—it explains why certain chords sound good together and how keys relate to each other. But learning from a static diagram feels like memorizing a phone book. MidiCircle.com transforms this essential concept into an interactive experience: plug in a MIDI controller and watch the circle respond as you play. 🎹 Real-Time Chord Detection Play any combination of notes and see the chord name appear instantly in the center of the circle. The app identifies inversions too—play E-G-C and it shows "C major — 1st inversion (3rd in bass)." Root notes highlight in green while other chord tones appear grey, teaching you which note is the foundation of each chord. 🔄 Major and Minor Visualization The outer ring displays major keys while an inner ring shows relative minors—the minor keys that share the same key signature. Toggle between Circle of Fifths layout (harmonically related notes adjacent) and Chromatic layout (matching piano key order). Hover over any note to see its major triad formula. 🔊 Built-In Audio Not every MIDI controller makes sound. Toggle on optional audio synthesis to hear sine wave tones for each note you press—no external speakers or software required. 📋 Technical Requirements MidiCircle.com works in Chromium-based browsers (Chrome, Edge, Brave) with a USB MIDI controller. WebMIDI isn't currently supported in Firefox or Safari.