Jazz Theory 8 7th CHORDS 1 The five Chord Qualities 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 Chords Ruler Quiz and Quiz Answers Ear tests 16 - 18 and Answers Lesson Material - General files Jazz Theory lessons online

JT 8.1 - 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

JT 8.2 - 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 :

JT 8.3 - 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 :

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 8.4 - 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 :

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 8.5 - 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 :

The diminished 5th interval gives this chord its name.

The chord symbol used is C ø , 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 8.6 - 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 :

(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).

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JT 8.7 - 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

Practise the five chord qualities in this order on the keyboard, so that only one finger moves from one chord to the next :

JT 8.8 - Related Chords

This subject is dealt with in detail in Lesson 19 and Lesson 20. The following are some general comments to give you a broader perspective at this point.

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 (see Lesson 20). 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 (see Lesson 20).

JT 8.9 - The 7th Chords Ruler

The 7th Chords Ruler is a simple device that helps you to determine any chord quality in any key.

1. Simply align the chord root name on the letter strip with the line labelled '1' on the chord interval strip.

2. Then read the letter names that make up the chord you want.

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JT 8.10 - Quiz

A.
Identify the following chords :

B.
Name the missing chord tones in these chords :

C.
1.Which are the three diminished 7th chords that together cover all 12 notes within the octave ?
2. What do the Co7 and Dbo7 chords form when combined ?
3. What do the Co7 and Do7 chords form when combined ?

D.
Write out on manuscript paper the five 7th chord qualities in all 12 keys (C G D A E B F# Db Ab Eb Bb and F) using the 7th Chord Ruler.

E.
Mark the major 7th chords in all keys on the Keyboard Diagrams.
Like this for the E major 7th chord :

Hint
Chords can be considered as stacks of minor 3rd and major 3rd intervals.
In E major 7th : E - G# = M3 (4 semitones), G# - B = m3 (3 semitones), B - D# = M3 (4 semitones).

1. M3 - m3 - M3 (4s - 3s - 4s) = major 7th chord
2. M3 - m3 - m3 (4s - 3s - 3s) = dominant 7th chord
3. m3 - M3 - m3 (3s - 4s - 3s) = minor 7th chord
4. m3 - m3 - M3 (3s - 3s - 4s) = half diminished chord
5. m3 - m3 - m3 (3s - 3s - 3s) = diminished 7th chord

F.
Mark the dominant 7th chords in all keys on the Keyboard Diagrams.

G.
Mark the minor 7th chords in all keys on the Keyboard Diagrams.

H.
Mark the half diminished chords in all keys on the Keyboard Diagrams.
(When writing out this chord do you get a feeling of "I have been here before?")

I.
Mark the diminished 7th chords in all keys on the Keyboard Diagrams.

J.
Write the five 7th chord qualities (maj7 - dom7 - min7 - ø - o7) in all keys on the Chord Letters Diagrams.

Example for the C chords :

Quiz Answers

JT 8.11 - Ear tests 16 - 18

First listen to Audio Demo 1.
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.

Audio Demo 2 plays the five qualities : maj7th - dom7th - min7th - half dim. - dim7th.

Ear test 16 - 7th chords. Determine the chord 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).

• 1 - 3 - 5 - 7 = major 7th chord

• 1 - 3 - 5 - b7 = dominant 7th chord

• 1 - b3 - 5 - b7 = minor 7th chord

• 1 - b3 - b5 - b7 = half diminished chord

• 1 - b3 - b5 - 6 = diminished 7th chord

Each number plays one of the above 7th chords :

JT 8.12 - Lesson Material