Jazz Theory 1 SEVENTH CHORDS General Description The Major 7th chord The Dominant 7th chord The Minor 7th chord The Half Diminished chord The Diminished 7th chord The Five 7th Chord Qualities Related chords The 7th Chord Qualities Ruler Quiz and Quiz Answers Downloading Bay Jazclass Links Seventh Chords in all 12 keys

JT 1.1 - General Description

A 7th chord contains four notes.
The four notes of a 7th chord are (like a 3-note triad chord) stacked in thirds on top of one another.

When the chord is in root position the notes occur either

• on successive lines

• or in successive spaces on the music stave.

You can also imagine the 7th chord as a triad chord with an additional note placed on top. The interval this top note makes with the chord root is a 7th (major, minor or diminished).

There are five fundamental qualities of 7th chords.

They are : the Major 7th chord the Dominant 7th chord the Minor 7th chord the Half Diminished chord the Diminished 7th chord

(Pastels on acrylics by Michael)

JT 1.2 - The Major 7th Chord

A major 7th chord can easily be constructed by selecting the 1st (tonic) 3rd , 5th and 7th note of any major scale :

Audio 1

Measured from the root (bass note) the major 7th chord consists of :

• a major 3rd (M3),

• a perfect 5th (P5), and

• a major 7th (M7) interval.

JT 1.3 - The Dominant 7th Chord

The Dominant 7th chord can be formed by lowering the 7th of the major 7th chord.
For example :

Audio 2

The Dominant 7th chord consists of :

• a major 3rd (M3),

• a perfect 5th (P5), and

• a minor 7th (m7) interval.

The major 3rd and minor 7th are the characteristic intervals for the dominant 7th chord.

The chord symbol used is C7.

This is the most commonly used 7th chord in classical and traditional music. Its dominant quality is not indicated in the chord symbol and therefore 'understood'.
However it is important to realise that this chord is merely one of five different qualities of 7th chords.

JT 1.4 - The Minor 7th Chord

The Minor 7th chord can be formed by lowering the 3rd of the dominant 7th chord.
For example :

Audio 3

The minor 7th chord consists of :

• a minor 3rd (m3),

• a perfect 5th (P5), and

• a minor 7th (m7) interval.

The minor 3rd and minor 7th are the characteristic intervals for the minor 7th chord and give this chord its name.

The chord symbols used are Cm7 or Cmin7 or C -7.

JT 1.5 - The Half Diminished Chord

The Half diminished chord can be formed by lowering the 5th of the minor 7th chord.
For example :

Audio 4

The half diminished chord consists of :

• a minor 3rd (m3),

• a diminished 5th (o5), and

• a minor 7th (m7) interval.

The diminished 5th interval gives this chord its name.

The chord symbol used is Cø , or in old sheet music Cmin7(b5).

The half diminished chord quality is only present as a 7th chord.
The 7 is therefore omitted from the symbol and the name.
(A half diminished 9th chord is used in Jazz. It adds the 9th to the half diminished chord symbol.)

JT 1.6 - The Diminished 7th Chord

The Diminished 7th chord can be formed by lowering the 7th of the half diminished chord.
For example :

Audio 5

The diminished 7th chord consists of :

• a minor 3rd (m3),

• a diminished 5th (o5), and

• a diminished 7th (o7) interval.

(The diminished 7th is usually notated as a major 6th. For the C chord 'A' instead of 'Bbb').

The diminished 5th and diminished 7th intervals give this chord its name.

The chord symbols used are Co7 or Cdim7.

Note that for the diminished 7th chord the 7 must be used in its name and chord symbol to distinguish it from the diminished triad (Co or Cdim).

The diminished 7th chord is symmetric.
All four notes are spaced at equal intervals, a minor 3rd (3 semitones) apart :

Each of the four member tones can be regarded as the tonic of a chord in its own right.

In above example : Co7 = Ebo7 = Gbo7 = Ao7

There are therefore only 3 different diminished 7th chords in our (12 tonal) musical system. Which are they ? (See Quiz below).

JT 1.7 - The five 7th Chord Qualities

We now have met the five 7th chord qualities.

This is how they inter-relate, for the C 7th chord qualities and as major scale note numbers in any key :

Audio 6

When playing the five chord qualities in this order on the keyboard only one finger moves from one chord to the next :

JT 1.8 - Related Chords

The four triad qualities and five 7th chord qualities represent all the functional chord qualities in Jazz (and traditional Western Classical music and popular music).

All other chords are variations of these fundamental qualities. They produce extra colour but do not produce an additional quality.

For example the 6 and 69 chords (in C : C6 = C E G A , C69 = (C) E G A D) are variations of the basic major triad. Their functions in music are identical.

Likewise the minor 6 and minor 69 chords (in C : Cm6 = C Eb G A , Cm69 = (C) Eb G A D) are variations of the basic minor triad.

Chord extensions of the 7th chords that include the 9th, 11th and 13th all are chords that provide extra colour but do not alter the chord quality (and therefore its function) in any way. The same applies to chord alterations. This is very useful to know when you, as a relative beginner, come across some intimidating looking chord symbols. For example :   C13 b9 #9 #11   =   C E G Bb Db D# F# A A rather daunting looking thing. But all it really represents is a basic C7 chord with an extra bit of colour and tension thrown in. Play a normal C7 chord and Bob's your uncle. This is not to say that you should not use these extra colours, but it is important that you understand what is really functional and what is just icing on the cake. You often find that the chord alteration specified in the chord symbol accommodates a note in the melody. For example over a G7 #9 you may find a Bb (or A#) in the melody. There is therefore no need to play that note in your chord, for the melody will add the alteration effect in a subtle way to it anyway. (When improvising however, the altered chord will add colour and interest.)

JT 1.9 - The 7th Chord Ruler

This is a very handy device to help you identify any 7th chord quality in any key.
Simply align the chord root name on the letter strip with the line labelled '1' on the chord interval strip.

A 7th Chord Ruler is included in the Facts Sheet for this lesson.

Don't forget, if you have any questions please ask me. Happy studying ! Michael

JT 1.10 - Quiz (Seventh Chords in all keys)

A.
Identify the following chords :

B.
Name the missing chord tones in these chords :

C.
Which are the three diminished 7th chords that together cover all 12 notes within the octave ?

D.
Write down the five 7th chord qualities (in root position) in all 12 keys (C G D A E B F# Db Ab Eb Bb and F) using the 7th Chord Ruler above.

E.
Listen to the ear test audio and determine the quality of each chord.
Each chord is played 3 times : first twice as a broken chord ('arpeggio'), then once as a solid chord (all notes together).
All chords are in root position. The chord qualities in this test are :

major 7th (1 - 3 - 5 - 7)

dominant 7th (1 - 3 - 5 - b7)

Ear test 1 : 12 Chords

F.
Listen to the ear test audio and determine the quality of each chord.
Each chord is played 3 times : first twice as a broken chord ('arpeggio'), then once as a solid chord (all notes together).
The chord qualities in this test are :

major 7th (1 - 3 - 5 - 7)

dominant 7th (1 - 3 - 5 - b7)

minor 7th (1 - b3 - 5 - b7)

Ear test 2 : 12 Chords

It may help to listen first to Audio 7.
This spells out the major and minor triads and the start of a popular song to identify them :

1. major triad = 1 - 3 - 5 ---> Song : Michael Row the Boat

2. minor triad = 1 b3 - 5 ---> Song : Midnight in Moscow.

G.
Listen to the ear test audio and determine the quality of each chord.
Each chord is played 3 times : first twice as a broken chord ('arpeggio'), then once as a solid chord (all notes together).
All chords are in root position. The chord qualities in this test are :

major 7th (1 - 3 - 5 - 7)

dominant 7th (1 - 3 - 5 - b7)

minor 7th (1 - b3 - 5 - b7)

half diminished (1 - b3 - b5 - b7)

diminished 7th (1- b3 - b5 - 6)

Ear test 3 : 12 Chords

Don't be disheartened if you have trouble identifying the chords in the beginning. It takes some practice. I have included all three tests in the Downloading Bay for you to copy and listen to at home.

JT 1.11 - Downloading Bay