Harmony
Modulation: How a Key Change Is Confirmed
A modulation is not a chromatic chord; it is a new key confirmed by cadence. The routes into one, and how to read them off the page.
Key
The tonic and scale that a passage centres on, against which its notes and chords are heard.
Also called: key centre, tonal centre
A key is the tonic and scale that a passage or piece is organised around. C major, for example, uses the seven notes of the C major scale, with C as its tonic. The key signature indicates the key at the start of a piece, but the signature alone does not fix the key, because a major key and its relative minor share one. A key can change within a piece through modulation, when the tonal centre moves, or through tonicisation, a brief emphasis on a non-tonic chord, such as V of V. Keys are named by a letter and a quality, such as E♭ major or F♯ minor.
Related terms
- Key signatureThe sharps or flats written after the clef that set which notes are altered throughout a piece unless cancelled.
- TonicThe first degree of a scale, the note that a key is named for and that tonal music treats as its home and point of rest.
- TonalityA system in which pitches are organised around a tonic and a key, so that some notes and chords sound more stable than others.
- Relative keyThe major or minor key that shares the same key signature, with its tonic a minor third above or below.