It is vital to understand cadences if you want to write or analyse music. They are music’s version of punctuation, giving structure and space to a piece. This allows the listener to process what they are hearing, adding clarity to the music. They also instil a sense of direction in the music.

This blog will introduce the 4 types of cadences: how they are constructed, and what effect they have on the music. In order to get the most out of it, you need to understand how to name chords. Thankfully that’s what I wrote about last month! Click here to read that post.

This is part of my series ‘Music Theory: An Introduction”. For other blogs from this series click here.

Contents

1) Why Bother With Cadences?

2) The Perfect Cadence

3) The Plagal Cadence

4) The Imperfect Cadence

5) The Interrupted Cadence

1) Why Bother With Cadences?

Think of a speech - a good speaker will present a point, develop it, and then conclude their thoughts about it, before moving on to something new. Without the conclusion, the speaker leaves the listeners lost on how they feel about the point. Even worse, if the speaker was to move on to a new idea without concluding, they would be left with a confused and lost audience.

This works pretty similarly in music. A cadence is effectively the conclusion; it is a chord sequence that ends a phrase, a section, or a piece of music. Its primary function is to bring music to some form of stopping point, potentially creating space for something new. And just like a speech without a conclusion, a piece without cadences will leave an audience lost and confused.

As mentioned in the intro there are 4 types of cadences. Each providing a unique way of ending a phrase or section. We’ll begin with the perfect cadence.

2) The Perfect Cadence

A perfect cadence is the most resolved cadence available. You can consider it a musical full stop. Here is an example of it - pay attention to the end.

The perfect cadence is constructed by ending a phrase with a V - I chord sequence. In C major that would be a G Major chord to a C Major chord:

There are certain voice leading guidelines that should be followed when writing this cadence. In the example above, B should resolve to C. This is called the 7-1 rule. As the piece is in C Major, the B in the G Major chord is the leading tone (7th scale degree) of C Major. The leading tone has a strong pull to the tonic (the 1st scale degree - C). If we don’t follow that pull it can lead to the cadence feeling unsatisfactory. If you don’t believe me about the pull of the leading tone, try playing a C Major scale, and stop on the B! For a bit more about scale degrees and leading tones, click here.

To make a perfect cadence even stronger, we can add an extra note to the Dominant chord (the V chord) to make it a Dominant 7th. We do this by adding the note a third above the top note of the chord. With a G major chord, in the key of C Major, this would mean adding an F.

When specifying Dominant 7th chords, we add a 7 after the letter of the chord. So for example a C Dominant 7th chord would be called C7.

Note that G7 has F instead of F#. This is because we are in the key of C Major, and therefore we exclusively use notes from the C Major scale.

Here is an example of a V7 - I perfect cadence in C Major:

When using a V7-I chord sequence, we have a new guideline to deal with. Along with the 7-1 rule (B to C in this case), we also now have a 4-3 rule, as the 4th scale degree wants to resolve downwards to the 3rd scale degree. In this case we need F to move down to E.

You may have noticed that we didn’t include the G in the I chord for the example above. The 5th of the chord (the 3rd note) is not compulsory when constructing chords. So for C Major – C E G, the G is not compulsory, and in a G7 chord – G B D F, the D is not compulsory.

The new 4-3 rule is the reason V7-I is a stronger cadence than the V-I. Rather than just having one note desperately trying to resolve, we now have two.

There are two other important factors to consider when deciding how strong you want the perfect cadence to be:-

1) As discussed in last month’s blog, root position is the strongest version of the chord, so either putting the V7/V or the I in first inversion will have a serious impact on the sound of the chord.

2) Perhaps more unexpectedly the top note of the I chord also has a big impact. If the I chord has the tonic (1st scale degree) on top, the cadence will feel stronger than if it has the 3rd or 5th scale degree on top. For example in C Major, for a strong cadence you would want to make sure the C is on top. Have a listen to these 3 audio examples each with a different note on top:

As you can hear, the sound is so different that in American terminology they have different names based on strength! Perfect Authentic Cadence means a V / V7 - I cadence where both chords are in root position AND the 1st scale degree is on top of the I chord. Any other V / V7 - I cadence would be considered an Imperfect Authentic Cadence. As you’ll see later the use of the word Imperfect can be a bit confusing.

3) The Plagal Cadence

The plagal cadence also resolves to the I chord, and can make a phrase or section feel resolved. They are often mixed up with perfect cadences, in fact for the grade 8 ABRSM exam, one of the aural questions is to tell the difference between perfect and plagal cadences! You can hear it at the end of Handel’s Hallelujah Chorus here.

Some people refer to them as the ‘Amen’ cadence due to their strong association with gospel music. But it would be a mistake to listen to hymns and gospel music and assume every resolving cadence was a plagal cadence. The biggest difference in sound is the root movement of both chords. When both chords are in root position, the bass movement in a perfect cadence is a lot stronger than in a plagal cadence. Have a listen:

To construct a plagal cadence we use a IV chord instead of a V chord. So a plagal cadence is IV - I. Let’s look at an example of a plagal cadence in C Major:

Probably the biggest thing to think about with a plagal cadence is the 4-3 rule. As said above, the 4th scale degree really wants to resolve to the 3rd. In C Major that’s F to E. In fact it’s that 4-3 movement that gives the ‘A-men’ sound.

IMPORTANT: this rule does NOT apply to the bass notes. The bass movement (or root movement) should go IV - I. Only notes above the bass notes are affected by the 4-3 rule.

Again just like with the perfect cadence, the strength of the plagal cadence is determined by the note on top of the final I chord, along with any use of inversions.

4) The Imperfect Cadence

The imperfect cadence is the first cadence that doesn’t feel resolved! Not everything in music needs to feel resolved. What the imperfect cadence does is create space for those unresolved feelings to hang. It is often used at a halfway point in a section, giving space for a melody to repeat. This is because the unresolved nature of the cadence leads to an expectation of more music to follow. Because of this functionality Americans call it the half cadence. When used in this way you can consider the imperfect cadence to be like a comma.

Have a listen to this example of Minuet in G Major by Petzold:

In this piece we hear the melody twice, with two different endings. The first ending has an imperfect cadence, while the second ending has a perfect cadence.

It is worth mentioning that imperfect cadences can also be used to finish a piece, to give the music a sense of uncertainty. Have a listen to the end of Mozart’s Requiem - 1. Introitus for an example.

Unlike the plagal and the perfect cadences there isn’t a two chord formula for this one. The only key ingredient required is that the piece ends with a V (Dominant) chord. No V7 chords for this one.

5) The Interrupted Cadence

The final cadence functions very differently to the previous three. Rather than creating space for a new section or phrase, this cadence pretends it’s a perfect cadence, and then just when you were expecting the I chord you get the vi chord instead! Americans also have a different name for this one, calling it a deceptive cadence.

Here’s a good example of one with the first 3 chords of Beethoven’s “Les Adieux”.

Because the listener is expecting a I chord, the surprise of the vi chord instead provides momentum, which in itself creates space for something new.

To construct an interrupted cadence you prepare it the same way you’d prepare a perfect cadence with a V or V7 chord, but then resolve to vi. This works because vi shares two of the same notes as the I chord. Here’s an example of V7 – vi in C Major:

See how the 4-3 and 7-1 rules still need to be followed. The 4-3 makes F go to E, and the 7-1 makes B resolve to C. To really sell the interrupted cadence, it’s best to use root position chords - remember you want the vi chord to feel unexpected, so the stronger the expectation is for a perfect is cadence, the bigger the surprise.

It is important to note that although the most likely chord the interrupted cadence lands on is a vi chord, it can also end on other chords. In Debussy’s ‘The Girl with the Flaxen Hair’, there is an interrupted cadence that goes V-IV. Click here a listen. The IV chord lands at 1:35 in the video. Regardless of what chord is used, the premise remains the same – the cadence leads you to expect the movement back to the I chord, but instead something else happens.

And that’s about it for this month! We have 4 important cadences here that you want to become familiar with. Perfect, Plagal, Imperfect, and Interrupted. When listening to music in the future, see if you can spot them. Ultimately, make sure when composing you use these to add structure and space to your music.

Dan