As with all style composition work, the more you can listen widely and find your own examples of cadence patterns and textures to steal, the better your work will sound!
Perfect cadences simply go from V – I, usually in root position (i.e. the root note of each chord in the bass). In addition, to make them more final, the tune tends to go by step to the tonic note (2-1 or 7-8).
The two most common decorations of this basic pattern are shown below.
The chord V is decorated by a double appoggiatura that takes the form of the second inversion tonic chord. We usually label it as in the example below as a decoration of V even though the notes in the first chord are from chord I:
Note that the G is doubled in both chords and that other voices tend to go down by step from the 6/4 to the 5/3 in thirds (or sixths).
Here is an example from Haydn’s String Quartet Op. 55 No. 1. The voice leading is basically the same as the simple example above:
There are some nice details to take notice of, starting with the simplest:
- the melody tends to stop on the tonic note once it arrives on it rather than mess around any further
- the second violin adds a D at the end of the third bar to make it a dominant seventh
- the first violin adds a C# appoggiatura against this seventh
- the V is approached from chord IV and Haydn briefly tonicises this subdominant chord by approaching it from a perfect cadence of its own, complete with G naturals to make the first bar a dominant seventh in D major.
ii – V – I (supertonic approach)
The other very common cadence is to approach chord V from chord ii, often in first inversion and quite often with an added seventh as well as in the example below (added seventh in red makes it 6/5 – a first inversion seventh):
Here is an example from the end of the first movement of Haydn’s Op. 20 No. 1 String Quartet. Notice that the V is also decorated by a cadential six-four as above:
Although this is the final full cadence, it is not actually the end of the movement. Having arrived nice and clearly on the tonic, Haydn adds a coda with some much less emphatic messing around. First, the lower and upper strings take turn to play a little closing figure that incorporates a cadence at the end each time:
At the very end, Haydn finishes with some messing around over a pedal and a long triple appoggiatura (technically a suspension) on the final chord: