Path
What to study before Modulation
A change of tonal centre confirmed by a cadence, not merely a chord from outside passing through. Below, the concepts that come before, in the order in which one explains the next. Signed in, you see the same path minus what you already hold: your path.
Notes and semitones
The seven letter names, the accidentals that alter them, and the semitone as the system's smallest step.
Intervals
The distance between two notes, measured by a number taken from the letter names and a quality taken from the semitones.
Major scale
Seven degrees built on a fixed sequence of tones and semitones, and the reference everything else is measured against.
Key signatures
The fixed accidentals at the start of the staff, their invariable order, and the circle of fifths that organizes them.
Triads
Three-note chords stacked in thirds, and the four qualities that result.
Diatonic harmony
The chords that arise from stacking thirds on each degree of a scale, and why each quality lands where it does.
Harmonic function
The role each degree plays — tonic, subdominant, or dominant — and the tension that moves one to the next.
Cadences
The formulas that close a phrase, and the degree of finality each one delivers.
Modulation
A change of tonal centre confirmed by a cadence, not merely a chord from outside passing through.