Pick a root and a quality
Choose any of the twelve roots (C through B) and a chord quality — major, minor, 7th, sus, diminished and more. The matching keys light up on the keyboard and the chord plays through a warm built-in synth.
Play, arpeggiate, and read the theory
Touch the keys directly (or use your computer keyboard), then switch on the arpeggiator to hear the chord unfold as a pattern. The theory panel names every note, its intervals, and the roman numeral in your chosen key.
Go further with PRO
AURA ONE unlocks the extended chord vocabulary, MIDI export, and every other app in the AURA Universe. A MIDI keyboard, if you have one, is detected automatically — no setup required.
Shortcuts
Questions
Do I need to know theory?
Not at all. Pick sounds you like and Harmony names them for you. The theory readout is there when you're curious, never in the way.
What's making the sound?
A small polyphonic synthesizer built right into your browser — two oscillators per voice through a filter and a touch of space. No plugins, no downloads.
Can I use a MIDI keyboard?
Yes. If your browser supports Web MIDI and a keyboard is connected, Harmony detects it automatically and lights up as you play.
What's the roman numeral for?
It tells you a chord's function within a key — how it behaves in a progression. Set your key at the top and the numerals update live.
Why is there no sound?
Browsers require a tap or key press before playing audio. Interact once and Harmony comes alive — headphones or speakers both work.