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Grade Six Music Theory - Harmony Lesson 4: Chord Progressions
The way we place chords next to each other is called "chord progression".
There is, of course, an infinite number of patterns of chord progressions, but there are also lots of "standard" patterns which our ears are very used to hearing.
Some chords sound extra-good when placed in certain progressions, so it's useful to learn what these progressions are.
We most often find "standard" progressions at the end of a phrase, or the end of a piece. Progressions at the end of a phrase or piece are called "cadences". We already studied cadences at grade 5, so pop back there to refresh your memory before continuing here.
Standard progressions also happen at non-cadence points in music. One very common pattern is called the "progression of 5ths".
In this lesson you'll find an introduction to:
- Perfect, imperfect and plagal cadences
- The progression of fifths
- The passing six-four and the cadential six-four
- The V-VI progression
You'll also start to understand about voice leading - which means working out which voice (e.g. bass, tenor, alto or soprano) should sing/play which note of the chord (no, it's not totally random!)
Cadences which occur at the end of a piece of music are nearly always either V-I (called a "perfect cadence") or IV-I (called a "plagal cadence"). Of these two, the perfect cadence is much more common. In real life, you could see other progressions at the end of a piece. But in the Grade Six Music Theory Exam, you will always be expected to end a piece with one of these two cadences.
(A piece ends with a double barline. Sometimes you might get a question which ends with a single barline - in that case it's not the actual end of the piece and so might not be a perfect or plagal cadence.)
Cadences which occur at the end of a phrase often, but not always, end on chord V (always major, even in a minor key). These are known as "imperfect" cadences.
In perfect cadences, the bass line falls by a fifth (or rises by a fourth) and the chords are in root position. So, the perfect cadence is Va - Ia.
Notice the voice leading - see how:
- the bass root rises by a fourth or falls by a fifth
- the doubled root of V, (G in this example), does not move - it becomes the 5th of I
- the 3rd of V, (B in this example), rises to the tonic of I
- the 5th of V, (D in this example), rises to the 3rd of I
In plagal cadences, the bass line falls by a fourth (or rises by a fifth) and the chords are usually in root position. The plagal cadence is IVa - Ia.
Notice the voice leading - see how:
- the bass root rises by a 5th, or falls by a 4th
- the doubled root falls to the 3rd of I
- the 3rd of IV falls to the 5th of I
- the 5th of IV does not move and becomes the doubled tonic of I
At the end of a questioning phrase (not at the end of a piece) we often hear an "imperfect cadence". This is any progession which ends up on a dominant, chord V. The most common imperfect cadences are:
Chords I, ii, IV and VI can also be used in the first inversion.
As we'll see, ii and II lead us to V in the progression of 5ths.
Listen to some imperfect cadences:
Notice the voice leading - see how:
- all chord notes except the bass move by the smallest possible step.
- if a note occurs in both chords (e.g. D in the first example), keep it in the same part (soprano here).
- other notes move by semitone, tone or third. Don't use larger intervals.
The Progression of Fifths
As you know, lots of music ends with a V-I (or i) cadence. This is because the notes in the V chord have a very strong "pull" towards those in a I chord.
For example, in the key of C major the chords V-I are G major - C major. The B in G major has a strong pull towards the tonic C. The semitone interval creates this strong pull.
Chord V is called the "dominant" for this reason - it's the most important chord after the tonic.
The 7th degree of the scale is called the "leading note" for the same reason - it feels like it leads somewhere, and the note it leads to is the tonic. We say that the leading note resolves to the tonic, because our ears feel satisfied when we hear the tonic played after the leading note.
So, chord I is most strongly related to chord V, its fifth.
In fact, every chord has a very strong connection with the chord which is a fifth higher. So, a chord of G has a strong link with the chord of D. In C major, D is chord ii (minor, not major), but that's ok - the link is still strong whether it's a major or a minor chord.
So far we have have discovered that the following chords have a dominant-tonic relationship: I-V-ii
We can carry on in the same way, until we've used up all the triads of C major:
We now have the complete cycle of the progression of fifths. All we need to do now is reverse the order, so that each "dominant" chord resolves to its "tonic":
Progression of Fifths: I - IV - vii° - iii - vi - ii - V - I
Here's an easy way to remember the order of chords:
Write down these numbers: 1 - 2 - 3 - 4 backwards, leaving a big gap between each number:
Then write the numbers 5 - 6 - 7 between those numbers, also backwards, and finish off by writing the Roman numerals below each number:
You will almost never see the whole series of fifths in use in one go. Usually just 2 or 3 chords taken from it at one time, for example, you might see vi - ii - V, or ii - V - I.
Often, the perfect cadence is stretched over three chords, in what's known as a "cadential 6-4". (See the lesson on figured bass for why!)
The cadential 6-4 progression uses the chords Ic - Va - Ia.
This is one of the very few occasions when you are allowed to use a second inversion (c) chord. (The inversions are very important here).
The bass note in chords Ic and Va is the same (in C major, for example, the bass note will be G in both chords).
The effect is that the bass stands still for a moment, while the chord above it changes. This "powers up" the bass note - our ears are expecting something important to happen - and when we finally hear the root position tonic chord Ia, with the bass dropping solidly by a 5th, our ears (and brains) feel satisfied.
Listen to a cadential 6-4 - pay particular attention to the bass line:
Tip! Always see if you can use a cadential 6-4 at the end of a piece in your grade six exam. They are not always possible, but if they work, they are great!
To use a cadential 6-4 correctly, you must be careful that
- the tonic of the Ic chord resolves to the 3rd of the Va chord
- the 3rd of the Ic chord resolves to the 5th of the Va chord
- the 5th (bass note) of the Ic chord becomes the tonic of the Va chord, i.e. the bass line keeps the same note in Ic-Va.
The Passing 6-4
The passing 6-4 is another progression where you are allowed to use a second inversion (6-4) chord. Unlike the cadential 6-4 where the bass note stays the same, in a passing 6-4 the bass moves by step. The second inversion chord falls on a weak beat of the bar.
Look at this passing 6-4 and notice that
- the bass line moves by step - C-D-E
- the second inversion chord (Vc) falls on a weak (middle) beat
- the other parts move by the smallest possible steps
V-VI Progression in Minor Keys
Finally, we'll take a look at a progression which is very common in minor keys. The V-VI progression is a little bit special, because you have to break one of the general rules of harmony in order to use it!
The most important rule in harmony is that you don't write consecutive fifths or octaves. You must never write consecutives. What are consecutives? Find out about consecutives here.
The rule which this progression breaks is "never double a major third" in root position chords. You'll learn more about the rules of harmony later, but if you want to check out this rule right now, read the passage on doubling in the rules of harmony.
In the Va-VIa progression, if you want to avoid writing a consecutive fifth or octave, you have to double a major third.
Here's an example - the key is A minor.
Chord V is E major, so there is a fifth between the E and B of the chord. Chord VI is F major, with a fifth between F and C.
In Va-VIa, the bass E has to move to bass F, G# is the leading note, so it moves to A. The B would logically move to a C, because it's a semitone step, but that would make a consecutive 5th with the bass, so we move it to A instead. The soprano E again would normally move by semitone step to F, but that would make a consecutive octave with the bass, so it has to move to C instead. These are the only legal moves, and the end result is a chord of F with two As - which is a major third above the root F.
Why is this just for minor keys? Because in major keys, chord vi is minor. In minor keys, chord VI is major. It's ok to double a minor 3rd in a root position chord, but not a major one!
Don't worry if all this sounds a bit too confusing for now! The important thing to remember is that there are some progressions which require special treatment. Keep that in the back of your mind, and when you start doing harmonisations and find yourself getting stuck, come back to this page and see if it makes a bit more sense!