Audio: cadence (0:10)
cadence plays a succession of cadences on a piano in the key of C. The cadence figure, the score, shows five types of cadence:
A cadence is a chord progression at the end of a section of music.
It is common practice in functional harmony to signal the end of a section. You cannot issue a verbal warning such as, The End is Nigh, because it will disturb the sensitive listener. Instead, you provide a musical clue, called a cadence.
A perfect or plagal cadence ending on the tonic brings a sense of closure, finally the music has made it back to base. These cadences are the musical equivalent of a full stop.
The cadential 6-4 also ends on the tonic but consists of three chords rather than the usual two. It is called 6-4 because a six-four triad is another name for a second inversion triad. This is usually the only time a second inversion triad is used in functional harmony, because it contains an interval of a fourth above the bass note and the fourth is a dissonant interval. For example, a second inversion C triad, GCE in the key of C, contains the dissonant fourth, GC. The bass note G, the fifth, is usually doubled in one of the three upper voices.
The imperfect and deceptive cadences are teasers. It is not clear what is going to happen next, the music has stopped half-way through a sentence. They are the musical equivalent of a comma.
A cadence can occur at the end of a section of music or at the end of a complete piece of music. A cadence at the end of a section uses either root position or first inversion chords, one at the end of a piece of music uses either root position chords or a cadential six-four.
You might find it helpful to start writing a section of functional harmony with a tonic chord in root position, then a gap, then the cadence. This leaves the hard bit to last, fleshing out the chord progression in the gap.
Cadence jargon is a language in itself. A perfect cadence is also called an authentic, closed or standard cadence. A plagal cadence is also called an Amen cadence. An imperfect cadence is a half cadence. A deceptive cadence is an interrupted cadence. This huge bag of weird and wonderful terms is used to describe what is actually just a simple progression with two chords.