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Understanding seventh chords in music

In this post we are going to explore seventh chords and their use in music. There are many different types of seventh chords that we will explore as we go along.

A seventh chord is another form of tertian chord and is the most common extension of the basic three note triad.

History of seventh chords
The use of seventh chords dates back to the Baroque and Renaissance period. Monteverdi even used them in his cadences back in his early baroque operas. Seventh chords add colour and excitement to a piece of music.
What is a seventh chord?
In order to understand seventh chords you need to make sure you understand basic triads first. Make sure to check out our chords blog post if you need anything clarifying. A seventh chord is built using one of the four main triads with a seventh above the root of that triad on the top.

Before moving onto the seventh chords let's remind ourselves of the four main triads which provide the base for our seventh chords!

The Four main triads:
  • Major Triad - this has the intervals of a major third and a perfect fifth above the root.
  • Minor Triad - this has the intervals of a minor third and a perfect fifth above the root.
  • Augmented Triad - this has the intervals of a major third and an augmented fifth above the root.
  • Diminished Triad - this has the intervals of a minor third and a diminished triad above the root.
In classical music there are five main seventh chords that you will see. These are the major seventh, dominant seventh, minor seventh, half diminished seventh and diminished seventh! These are all built using our four main triads.

 

There are a few more types of seventh chords but these are more commonly used in popular music.

Major Seventh
A major seventh chord is simply a major triad (major third and perfect fifth above the root) with a major seventh added above the root. A major seventh is eleven semitones above the root.

 

Below you can see a major seventh chord in the key of C. The notes in this are C, E, G, B.

There are a few different ways to notate a major seventh chord in music, including CM7. Upper case 'M' for the major chord, a lower case would imply a different chord.

 

Below you can see all the different ways that a major seventh chord is written in music:

A major seventh chord has a much softer sound than a dominant seventh and is used a lot in jazz music!

 

A great example to hear this chord in action is in Erik Satie's Gymnopedie No.1. You will hear a G major seventh chord and a D major seventh chord!

Minor Seventh
A minor seventh chord is a simply a minor triad (minor third and perfect fifth above the root) with a minor seventh above the root. A minor seventh is ten semitones above the root.

 

Written below you can see a minor seventh chord in the key of C. The notes in this chord are C, Eb, G, Bb. A minor triad and a minor seventh above it.

You would see this written as Cm7 or Cmin7 in your music. Lower case 'm' for the minor chord as, as we saw before, a capital M would imply a major chord.
The minor seventh chord has a jazzy feel. A great song to hear this chord in action is in Roberta Flack's Killing Me Softly.
Dominant Seventh
A dominant seventh chord is a simply a major triad (major third and perfect fifth above the root) with a minor seventh above the root. A minor seventh is ten semitones above the root.

 

Written below you can see a dominant seventh chord in the key of C major. The notes in this chord are C, E, G, Bb. C, E, G form the C major triad and the Bb on the top creates the dominant seventh.

You would see this written as C7 in your music. We simply remove the m when notating dominant seventh chords and leave just the number 7.
Dominant seventh chords are used a lot in blues music!
Half Diminished Seventh
A half diminished seventh is simply a diminished chord (minor third and a diminished 5th above the root) with a minor seventh above the root. A minor seventh is ten semitones above the root.

 

Below you can see a half diminished seventh chord in the key of C. The notes in this chord are C, Eb, Gb, Bb.

You will see this notated as either a small circle with a dash through it followed by the number 7 or by having a number 7, a flat sign and a number 5.
Half diminished chords are very good at giving a feeling of tension to your music!
Diminished Seventh
A diminished seventh is simply a diminished chord (minor third and diminished fifth above the root) with a diminished seventh above the root. A diminished seventh is nine semitones above the root. We sometimes refer to a diminished seventh as a fully diminished seventh chord.

 

Below you can see a diminished seventh chord in the key of C. The notes in this chord are C, Eb, Gb, Bbb

You would see this notated with a small circle and a 7. Co7 or by writing Cdim7.
Diminished seventh chords have a distinctive tense and scary feel - they sound very much like something you would hear in a scary movie!
Seventh Chord Inversions
As with our normal triads, seventh chords can also be inverted! If you are unsure about inversions in normal triads then it is essential that you read our article on this before embarking on this one!
 

As you know, we can have a root position chord, a first inversion chord and a second inversion chord!

A root position chord simply means the root of the chord is at the bottom.

First inversion means the second note (the third) of the chord is at the bottom.

Second inversion means the third note (the fifth) of the chord is at the bottom!

In seventh chords we have an extra inversion - third inversion!

A third inversion simply means that the seventh is at the bottom of the chord

Seventh Chord Inversions Labelling
As with all other chords, that are represented by Roman numerals or figured bass, seventh chords also can use these two methods.

A root position chord is represented by a small letter 'a' next to the Roman numeral.

A first inversion chord is represented by a small letter 'b' next to the Roman numeral.

A second inversion chord is represented by a small letter 'c' next to the Roman numeral.

And finally...

A third inversion chord is represented by a small letter 'd' next to the Roman numeral.

Below you can see the different inversions of chord I in C major!

Figured Bass Inversion Symbols - Seventh Chords
We can also represent these chord inversions using figured bass. Make sure to read the blog post on figured bass to learn about this in more detail but for now we will look at the basic figured bass labelling. Figured bass uses small numbers underneath the bass note which simply tell you how many notes above the bass note you need to play to form the required chord.

 

If your seventh chord is in root position this is represented simply with a number 7. The true figured bass would also include a 5/3 underneath the 7 but this is usually omitted. So this will simply mean you need to play the note a third above the bass, a fifth above the bass and the seventh above the bass. By doing this you will form a root position seventh chord above the bass note given.

If the seventh chord is in first inversion, this is represented with a 6/5. When writing out the figured bass we omit the 3 from the bottom of 6/5. So for a first inversion seventh chord we play a third above the bass, a fifth above the bass and a sixth above the bass!

 

If it is in second inversion, this is represented with a 4/3. When writing out the figured bass for a second inversion chord we omit the 6 above the 4. So for a second inversion chord we play a third above the bass, a fourth above the bass and a sixth above the bass!
If it is in third inversion, this is represented with a 4/2. When writing out the figured bass for a third inversion chord, we omit the 6 above the 4. So for a third inversion chord, we play a second above the bass, a fourth above the bass and a sixth above the bass!
FAQs
What are the most common seventh chords used in classical music?
  • Major Seventh Chord
  • Minor Seventh Chord
  • Dominant Seventh Chord
  • Diminished Seventh Chord
  • Half-Diminished Seventh Chord
How many notes are there in a seventh chord?

A seventh chord is built using a typical triad with one extra note added, the seventh!

What triads are used to base seventh chords on?

Each seventh chord is based on four different triads. These are the:

  • Major Triad
  • Minor Triad
  • Augmented Triad
  • Diminished Triad
Author: Jade Bultitude
Jade is an experienced musician and teacher as well as being the founder of Music Theory Foundations.
She has been helping people learn music theory for more than 10 years from pre school children all the way to degree level studies.
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