Cadences

The full cadence

I–IV–V–I · C – F – G – C · T–S–D–T

The full cadence: tonic, subdominant, dominant, tonic — the basic formula of harmony, the one that establishes a key. Each of the three primary triads appears once, and between them they hold all seven notes of the scale. If you can play this in a key, you can already accompany in it.

Authentic cadence (perfect cadence)

V–I · G – C · D–T

Dominant to tonic: the ending that sounds like a full stop. The leading note B pulls up to C, the dominant relaxes into the tonic. It is called perfect when both chords are in root position and the melody ends on the root — as here. Otherwise it is imperfect, and the ending sounds less final.

Plagal cadence

IV–I · F – C · S–T

Subdominant to tonic: the »Amen« at the end of hymns. Softer than the authentic cadence because no leading note pulls to the root — C is in both chords and stays put. It often follows an authentic cadence as a confirmation.

Half cadence

I–V · C – G · T–D

Ends on the dominant: a comma, not a full stop. The phrase stays open, you expect it to continue — typical at the end of an antecedent, which the consequent then answers with an authentic cadence. ii–V or IV–V are half cadences too: what counts is that the dominant comes last.

Deceptive cadence (interrupted cadence)

V–vi · G – Am · D–Tp

The dominant does not resolve to the tonic but to the relative minor: the ear expects C major and gets A minor. The leading note still rises, only the bass steps aside. That is how a phrase is extended — the real ending usually follows.

Phrygian half cadence (in A minor)

iv⁶–V · Dm/F – E · s–D

In minor: the subdominant in first inversion, with its third in the bass, falls a semitone to the dominant. That semitone step in the bass (F–E) sounds like the Phrygian mode, hence the name. You hear it in Baroque slow movements and in flamenco — as the core of the Andalusian cadence.

How to tell them apart

Listen to the last chord. Tonic at the end: authentic cadence (from the dominant) or plagal cadence (from the subdominant). Dominant at the end: half cadence. A dominant that does not go to the tonic: deceptive cadence. The functions — T, S, D — are given with every example; the terms explain them.