The 12 Notes

What this section teaches

Western music builds everything from twelve pitch classes — the twelve distinct notes inside every octave, after which the pattern repeats with doubled frequency. Seven carry plain letter names, A through G; the other five live between them and answer to two names each (F# is Gb), a duality called enharmonic spelling. None of this is arbitrary: each note is a physical vibration rate, anchored by the modern tuning standard of A at 440 Hz, with every other pitch placed by equal temperament — the compromise tuning that makes all twelve keys equally usable.

How to use these pages

Each note's page is its complete dossier: reference frequency and MIDI number, enharmonic spelling, the four triads built on it, the keys that contain it, and the scales it appears in. Use the pages as lookup — what exactly is D#, and where does it live? — or read all twelve in sequence as a first tour of the pitch system. Nothing here requires reading notation; every fact is stated in note names and numbers.

Where to go next

Notes alone are just points. The music starts with the distances between them — the intervals — which combine into scales and stack into chords. If you're following the site as a course, intervals are the natural second chapter.