A cadence is a chord progression of at least 2 chords that ends a phrase or section of a piece of music. The easiest way to understand cadences in music is to think of the punctuation you find at pauses and breaks in spoken speech. Take the following spoken rhyme:
Notice how there are different pauses at the end of each line. The 2nd and 4th line have a period (full stop) at the end – this is because the rhyme could end there and still make sense – it is a definite pausing point.
The 3rd line has a comma at the end of it because this shows that the rhyme is going to continue. The rhyme pauses, but is clearly going to continue because it wouldn’t make sense if it stopped at the end of the 3rd line.
These pauses are weak/strong depending on how much of a sense of completion is created. In a similar way, music is divided up into phrases/sections. When you listen to the end of a phrase in music it either sounds like it is finished or unfinished. Whether it sounds finished or unfinished depends on which cadence is used.
Types of Cadences
There are 4 main types of cadence you will come across – 2 of them sound finished, whilst the other 2 sound unfinished:
Both of the finished cadences sound finished because they end on chord I.
Authentic Cadence/Perfect Cadence
This goes from chord V to chord I (this is written V-I). It is the cadence that sounds the “most finished”.
In the key of C major, it goes from V (G) – I (C) and it sounds finished.
A Plagal Cadence goes from chord IV to chord I (IV-I). It is sometimes called the “Amen Cadence” because the word “Amen” is set to it at the end of many traditional hymns.
In the key of C, this will be F (IV) and C (I).
Both of these cadences sound finished because they end on chord I, but they each have their own characteristic sound.
Now let’s have a look at the unfinished cadences:
Unfinished cadences sound unfinished because they don’t end on chord I. When you hear an unfinished cadence at the end of a phrase it sounds like the music should not stop there – it sounds like it should continue onto the next section.
Half Cadence/Imperfect Cadence
A half cadence/imperfect cadence ends on chord V. It can start on chord I, II or IV.
In C major, it is C (I)- G (V) or Dm(II)- G(V) or F(IV)-G (V). It sounds more like a question mark, leaving the listener expect some sort of resolution to come after the V chord.
Interrupted Cadence (Deceptive Cadence)
An interrupted cadence ends on an unexpected chord – the music literally does sound like it has been “interrupted”. The most common chord progression you will come across is from chord V to chord VI (V-VI). So, C major it is G (V)- Am(VI). As the listener expects the I chord to follow the V, The VI chords creates a deception and it is more like an exclamation point (!).
Again, the music sounds like it is unfinished – it sounds like it has just paused and should now continue onto a new section.
Apart from these 4 popular cadences, there is another cadence that also gets used quite frequently. It is called the minor plagal cadence. It has a finished sound but with a strong touch of sadness. The idea is to use Minor IV instead of major IV. In the key of C major it should be Fm and C instead of F and C. A very common way to use this cadence is to play Major IV, followed by the minor IV and then the I chord for the final resolution.