A cadence is a chord progression consisting of two different chords and it is used at the end of a phrase.
There are four common cadences you should know about in music theory.
- The Perfect Cadence (Authentic Cadence)
- Plagal Cadence
- Imperfect Cadence (Half Cadence)
- Interrupted Cadence (Deceptive Cadence)
There are two other labels, related to the perfect cadence, that we will also discuss in this blog post. These are the authentic cadences: Perfect Authentic Cadence and Imperfect Authentic Cadence.
Why do we have cadences?
Music is broken up into phrases, very much like sentences in language! Take a look at the children’s song ‘Twinkle Twinkle Little Star’.
Twinkle Twinkle Little Star,
How I wonder what you are,
Up above the world so high,
Like a diamond in the sky,
Twinkle Twinkle Little Star,
How I wonder what you are.
Notice how there are natural pauses at the end of certain sentences. These pauses allow the paragraph to breathe and also help to give it structure! We also have these in music, these pauses in a melody are signified by the use of cadences!
Cadences can signify the end of a phrase, show continuation of the phrase or a cadence can simply signify a change of key in the phrase.
Let’s look at the four different types of cadence! These cadences divide into two categories. The cadences that sound finished or complete because they finish on chord I and cadences that do not sound finished or complete.
Perfect Cadence (Authentic Cadence)
The perfect cadence, sometimes referred to as an authentic cadence, is used to show that a piece or phrase is finished! A perfect cadence is like the full stop at the end of the piece of music.
The chords we use in a perfect cadence are V-I.
If we were in the key of C major this would be a G major chord (V) followed by a C major chord (I).
Although these labels are not used in the UK, there are some alternative labellings for our perfect cadences although from now we will refer to them as Authentic Cadences!
Perfect Authentic Cadence
As like a normal Authentic Cadence, the chords used in this cadence are Chord V – Chord I. However, there are two extra rules need to create a Perfect Authentic Cadence. This is that both of these chords must be in root position and the upper voice finishes on the first degree of the scale. Below you can see an example of a perfect authentic cadence.
Imperfect Authentic Cadence
The imperfect authentic cadence also consists of the chords V-I. However, what makes the Imperfect Authentic Cadence different is that it does not have to meet the same requirements as the Perfect Authentic cadence!
The two labels Perfect Authentic Cadence and Imperfect Authentic Cadence are not commonly used in the UK but it is always worth being aware of them!
A plagal cadence is another type of cadence that signifies the end and makes a phrase sound finished. However, this one is most commonly used in hymns. It is sometimes referred to as the ‘Amen’ cadence!
The chords used in a plagal cadence are chord IV-I. As the Plagal cadence also finishes on chord I, very much like the perfect cadence, this is what makes it sound complete.
If we were in the key of G major this would be a C major chord (IV) followed by a G major chord (I).
Imperfect Cadence (Half Cadence)
An imperfect cadence, otherwise known as a half cadence, is one that sounds unfinished! If you use an imperfect cadence, the phrase will sound incomplete.
An imperfect cadence feels almost like a comma in a sentence, the phrase has not yet finished and still has somewhere to go. An imperfect cadence always finishes on chord V!
There are three different options of the two chords in an imperfect cadence:
- I – V (tonic chord followed by a dominant chord)
- II – V (supertonic chord followed by a dominant chord)
- IV – V (subdominant chord followed by a dominant chord)
Interrupted Cadence (Deceptive Cadence)
An interrupted cadence is our final cadence. This cadence is a surprise as we are not expecting the second chord in the cadence, hence the deception in ‘deceptive cadence’! This cadence will also make a phrase sound incomplete!
An interrupted cadence is a dominant chord followed by a submediant chord.
If we look at an interrupted cadence in C major, this would be a G major chord (V) followed by an E minor Chord (vi).