Harmony
Cadences: How Phrases End in Tonal Music
Authentic, half, plagal and deceptive cadences, and the real reason a close sounds strong: what happens in the bass, the top voice and the metre.
Perfect authentic cadence (PAC)
A V to I cadence with both chords in root position and the tonic in the top voice. It is the strongest and most final close in tonal music.
Also called: PAC, Perfect cadence, Perfect close
A perfect authentic cadence is a V to I, or V7 to I, close in which both chords are in root position and the tonic is the highest note of the final chord. In C major, G or G7 moving to C in root position, with C in the soprano, is a PAC. Each condition matters. An inverted tonic, or the third or fifth of the tonic in the soprano, produces an imperfect authentic cadence, which is weaker. The bass moving from G to C gives the strongest root motion, and scale degree 1 in the soprano makes the arrival sound like an ending. Many tonal phrases end on a PAC, while others use an imperfect form. A PAC is often prepared by a predominant such as IV or ii6, which gives the dominant its purpose.
Related terms
- Authentic cadenceA close from the dominant to the tonic, V to I or V7 to I, which ends a phrase. Its perfect and imperfect forms differ in strength.
- CadenceA conventional pattern at the end of a phrase or section that gives a sense of closure, pause or continuation.
- Dominant seventh chordA major triad with a minor seventh above the root, such as G B D F. Its tritone pulls strongly toward the tonic.
- Root positionA chord arrangement in which the root is the lowest note in the bass, so the chord rests on its fundamental.
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Harmony
Voice Leading: Why the Rules Exist in Four-Part Writing
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