Cadences
Music theory · Tonal harmony · Level 3 · 14 min
A cadence is the harmonic formula that ends a musical phrase, just as punctuation ends a written sentence. Some are full stops, others commas or question marks.
| Cadence | Progression | Effect |
|---|---|---|
| Perfect authentic cadence (PAC) | V(7) → I, both in root position, tonic in the top voice | full stop |
| Imperfect authentic cadence (IAC) | V → I with an inverted chord, or without the tonic on top | semicolon |
| Half cadence | … → V (stopping on the dominant) | comma, question |
| Plagal cadence | IV → I | “Amen”, settling |
| Deceptive (interrupted) cadence | V → vi | surprise, keeps going |
Listen to them in order: perfect (bar 1), half (bar 2), plagal (bar 3), deceptive (bar 4).
M:4/4
L:1/4
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
K:C
[V:RH] "G7"[FB]2 "C"[Ec]2 | "C"[Ec]2 "G"[DB]2 | "F"[Fc]2 "C"[Ec]2 | "G7"[FB]2 "Am"[Ec]2 |]
[V:LH] "_V7"[G,D]2 "_I"[C,C]2 | "_I"[C,G,]2 "_V"[G,,G,]2 | "_IV"[F,A,]2 "_I"[C,G,]2 | "_V7"[G,D]2 "_vi"[A,C]2 |]
The deceptive cadence, or the art of surprise
After G7 the ear expects C… and gets A minor. The upper notes move exactly as in a perfect cadence (B rises to C, F falls to E); only the bass goes to A instead of C. Composers use it to extend a phrase: the real perfect cadence arrives a few bars later.
A cadence specific to minor
The Phrygian half cadence (iv6 → V in minor, e.g. D minor/F → E in A minor) moves the bass down a semitone to the dominant. You hear it constantly in Baroque music, at the end of a slow movement leading into a fast one.