Harmony
Harmonic Sequences and Circle Progressions That Modulate
Descending fifths, ascending 5-6 patterns, Pachelbel loops: how sequences work, when they modulate, and how to write them.
Sequence
A pattern repeated at successively higher or lower pitches, usually a motif or chord group restated a step up or down.
Also called: Melodic sequence, Harmonic sequence
A sequence is a short pattern repeated at a different pitch level, usually each time a step higher or lower. A melodic sequence repeats a motif, and a harmonic sequence repeats a chord pattern. A common example is the descending fifths sequence, where each chord's root falls by a fifth. In C major, D7, G7, C7, F is a sequence of this kind, and each chord is the dominant of the next. A real sequence keeps the intervals exact at every step, while a tonal sequence adjusts the intervals to stay in the key. Sequences build momentum, because the ear anticipates the next repetition. They are common in Baroque and Classical music, and they are a standard way to extend a passage or move between keys.
Related terms
- Circle progressionA chord progression in which each root moves by a fifth, usually down, so the chords trace the circle of fifths.
- MotifA short melodic, rhythmic or harmonic idea that recurs and develops across a piece, serving as its basic thematic unit.
- Chord progressionA succession of chords in a particular order, described by their roots and functions, such as I, IV, V, I in a key.
- Secondary dominantA dominant chord that tonicises a diatonic chord other than the tonic, written with a slash such as V7/V, which is D7 in C major.