CHORD FAMILIES

One of the most important skills for any musician is to be able to recognise and utilise chord families. A chord family is a group of chords that all contain notes that come from the same scale. We use the concept of chord families to understand how different chords relate to each other, to compose effective pieces of music and to improvise over a set of chord changes.

To understand chord families, first we need to revisit the major scale. Let's look at the C Major scale. In the example below, I've numbered each degree of the scale from 1 to 7 - in the same way that we've sung the scale in our ear-training lessons.

In music theory, we usually use roman numerals to label these degrees of the scale. Using roman numerals, the C major scale looks like this:

We can build triad chords on each degree of the scale by stacking notes in thirds on top of each of these notes. You'll notice that every note in every chord comes from the C Major scale - we haven't had to use any accidentals. We can describe all of these chords as being diatonic to C Major.

Because the major scale uses a combination of tone and semitone steps, the sound or quality of each chord changes as we go up the scale. Chord I is a Major chord, Chord II is minor, Chord III is minor, Chord IV is Major, Chord V is Major, Chord VI is minor and chord VII is diminished.

The 'rule' for remembering the qualities of the major chord families is: MAJOR, minor, minor, MAJOR, MAJOR, minor, diminished

Each of the major-scale chord families contain

THREE MAJOR CHORDS (I, IV, and V)

THREE MINOR CHORDS (II, III and VI) and

ONE DIMINISHED CHORD (VII)

This is true no matter which major scale we are using. Look at the examples below:

THE CHORD FAMILY OF D MAJOR

THE CHORD FAMILY OF B FLAT MAJOR

THE PRIMARY CHORDS

The Major chords in the major-scale chord families (built on note I, IV and V) are often referred to as primary chords. In classical music theory, primary chords are labelled using capital letters, and capital roman numerals.

THE SECONDARY CHORDS

The other chords in the chord family (chords II, III, VI and VII) are often referred to as secondary chords. These days it's common to see these chords labelled with a capital letter, followed by a symbol to indicate the chord quality - for example on most guitar tabs, the D minor chord will be written either as Dm or D-, and the B diminished chord will be written as either Bdim or Bo. In classical music, minor chords are usually just written as lower case letters (for example D minor is usually just written as 'd', and diminished chords are written in lower case, followed by the diminished symbol; eg bo or bdim. You will need to be familiar with both ways of writing these chords.

Roman numerals for secondary chords are also written in lower case in classical music:

Here is the C Major scale again, with both primary and secondary chords marked in upper and lower case:

Exercises

EXERCISE 1 Label the chords in this chord family using classical notation and roman numerals (as in the example above)

EXERCISE 2 Label the chords in this chord family using classical notation and roman numerals

When you're trying to work out a diatonic chord progression:

1) Work out the key of the piece

2) Count up degrees of the scale (lines and spaces) from the tonic to the root of the chord.

3) Write this number as a Roman Numeral

4) Work out the chord quality (remembering that the 'rule' is MAJOR, minor, minor, MAJOR, MAJOR, minor, diminished

For example, we can tell from the key signature in the example below that we are in the key of Eb Major. We can find Eb (the tonic) on the bottom line of the stave. If we count up the stave (counting the 'E line' as 1), we can see that the first chord is chord iii. The root of the chord is G, and the quality of the iii chord is minor, therefore the chord is G minor (or 'g').

EXERCISE 3 Label the chords below using classical notation and Roman Numerals

EXERCISE 4 Label the chords below using classical notation and Roman Numerals

Things get a little trickier when there's no key signature. When that's the case, we need to look for clues to help us work out the key signature before we can identify the chords. There are several ways to do this.

Firstly, can you arrange all the accidentals so that they make a recognisable key signature? In the stave below, there are lots of accidentals, but on closer inspection you will notice that the only notes that have been flattened are E, A and B. We can therefore safely assume that this extract is in the key of Eb.

Another clue to help determine the key can be to look for what chord the piece of music starts and finishes on. One or both of these chords will often be the tonic (I) chord, but this isn't always reliable.

A more effective way to help identify the key is to look for patterns within the chord progressions; for example:

If there are two minor chords in the extract that are a tone apart from each other, these will most likely be chords ii and iii.

If there are two major chords whose roots are a tone apart from each other, these will be chords IV and V.

If there's a diminished chord, it will be chord vii.

If there's a minor chord with a Major chord a semitone above it, these will be chords iii and IV.

INVERSIONS

When a chord is voiced over a note other than the root of the chord, it is called an inversion. The notes C, E and G always make a C major triad, no matter what order they appear in. Below are some examples of common C Major chord voicings. (All of these examples contain only the notes C,E and G)

IDENTIFYING inversions

There are a couple of ways in which inversions are commonly labelled. Whichever system you use, there are two things you need to know in order to correctly label an inversion: The name of the triad, and which note appears at the bottom of the triad.

System One: Root Position, 1st Inversion, 2nd Inversion

In this system, chords are said to be in 'root position' if the lowest note in the chord is the root or the tonic.

When the 3rd of the chord is the lowest note, we refer to the chord as a 1st Inversion

When the 5th of the chord is the lowest note, we refer to the chord as a 2nd Inversion

System Two: SLASH CHORDS

In contemporary music (Jazz and rock) we often encounter inversions written as slash chords. In this system, the chord is written to the left of the slash, with the lowest note of the chord voicing written to the right:

C/E = 1st inversion (a C triad voiced over the third) and

C/G= 2nd inversion (a C triad voiced over the fifth)

System Three: BRACKETS

In classical music, inversions are often indicated as a lower case letter written in brackets after the chord name. In this system, the bracketed letter indicates which type of inversion is being used.

C or C(a) = Root Position

C(b) = 1st Inversion (the third is the lowest note of the chord)

C(c) = 2nd Inversion (the fifth is the lowest note in the chord)

The last system for writing and labelling chords and inversions is called FIGURED BASS. This is a short-hand for writing chords that was popular in the Baroque Period. We will look at Figured Bass in the next lesson...

NEXT LESSON: FIGURED BASS