4.2 Cadences

What a cadence is

A cadence is a harmonic close, like punctuation at a phrase's end. The main types are authentic, plagal, half, and deceptive.

Authentic and plagal

An authentic cadence is V–I (a PAC, perfect authentic, if both are root position with tonic on top — the strongest ending). A plagal cadence is IV–I (the 'Amen' cadence).

Half and deceptive

A half cadence ends on V (unfinished, needing continuation). A deceptive cadence is V–vi, surprising the ear by avoiding the expected tonic.

Key terms

Cadence

a harmonic close at a phrase's end

Authentic cadence

V–I (PAC is the strongest)

Plagal cadence

IV–I (the 'Amen' cadence)

Half cadence

ends on V (unfinished)

Deceptive cadence

V–vi (avoids the expected I)

Try an AP-style question

A perfect authentic cadence (PAC) requires…

1. V–vi with the tonic in the bass
2. V–I, roots in bass, tonic on top
3. I–V, ending on the dominant
4. IV–I with any note in the soprano