Chord Construction II: Seventh Chords

To this point in the series, we have defined and constructed each type of chord according to a formula based on the major scale with the same root note as the chord.

But each type of chord can also be defined by the intervals it contains.

This post will analyze the intervals contained in the seventh chords covered to this point in the series:

  • Major seventh.
  • Dominant seventh.
  • Minor seventh.
  • Minor seventh, flat five.

Common fingerings for seventh chords, along with instruction on how to play them with any root note are provided in the post entitled Seventh Chords.

Major Seventh Chords

A major seventh chord contains the first, third, fifth and seventh degrees of the major scale with the same root note.  So a major seventh chord contains six intervals: 

  • The distance between the first and third notes.
  • The distance between the third and fifth notes.
  • The distance between the fifth and seventh notes.
  • The distance between the first and fifth notes.
  • The distance between the first and seventh notes.
  • The distance between the third and seventh notes.

For example, a Cmaj7 chord (fig.2a) contains the notes C, E, G and B — the first, third, fifth and seventh notes in a C major scale (fig.1). 

Fig.1

So a C major chord contains six intervals:

  • The distance between the C and the E (the first and third notes in a Cmaj7 chord and in a C major scale) is a major third (fig.2b). It contains three scale steps (C, D and E) and four half steps between the two notes. 
  • The distance between the E and the G (the third and fifth notes in the chord and the first and flatted third notes in an E major scale) is a minor third (fig.2c). It contains three scale steps (E, F an G) and three half steps between the two notes.
  • The distance between the G and the B (the fifth and seventh notes in the chord and in a C major scale) is a major third (fig.2d). It contains three scale steps (G, A and B) and four half steps between the two notes. 
  • The distance between the C and the G (the first and fifth notes in the chord and in a C major scale) is a perfect fifth (fig.2e). It contains five scale steps (C, D, E, F and G) and seven half steps between the two notes.
  • The distance between the C and the B (the first and seventh notes in the chord and in a C major scale) is a major seventh (fig.2f).  It contains seven scale steps (C, D, E, F, G, A and B) and 11 half steps between the two notes.
  • The distance between the E and the B (the third and seventh notes in the chord and the first and fifth notes in an E major scale) is a perfect fifth (fig.2g). It contains five scale steps (E, F, G, A and B) and seven half steps between the two notes.

Fig.2

So a major seventh chord contains a:

  • Major third interval between the first and third notes.
  • Minor third interval between the third and fifth notes.   
  • Major third interval between the fifth and seventh notes. 
  • Perfect fifth interval between the first and fifth notes.
  • Major seventh interval between the first and seventh notes. 
  • Perfect fifth interval between the third and seventh notes.   

Dominant Seventh Chords

A dominant seventh chord contains the first, third, fifth and flatted seventh degrees of the major scale with the same root note.  So a dominant seventh chord contains six intervals: 

  • The distance between the first and third notes.
  • The distance between the third and fifth notes.
  • The distance between the fifth and flatted seventh notes.
  • The distance between the first and fifth notes.
  • The distance between the first and flatted seventh notes.
  • The distance between the third and flatted seventh notes.

For example, a C7 chord (fig.3a) contains the notes C, E, G and Bb — the first, third, fifth and flatted seventh notes in a C major scale.

So a C7 chord contains six intervals:

  • The distance between the C and the E (the first and third notes in a C7 chord and in a C major scale) is a major third (fig.3b). It contains three scale steps (C, D and E) and four half steps between the two notes. 
  • The distance between the E and the G (the third and fifth notes in the chord and the first and flatted third notes in an E major scale) is a minor third (fig.3c). It contains three scale steps (E, F and G) and three half steps between the two notes.
  • The distance between the G and the Bb (the fifth and flatted seventh notes in the chord and the first and flatted third notes in a G major scale) is a minor third (fig.3d). It contains three scale steps (G, A and B) and three half steps between the two notes. 
  • The distance between the C and the G (the first and fifth notes in the chord and in a C major scale) is a perfect fifth (fig.3e). It contains five scale steps (C, D, E, F and G) and seven half steps between the two notes.
  • The distance between the C and the Bb (the first and flatted seventh notes in the chord and in a C major scale) is a minor seventh (fig.3f).  It contains seven scale steps and 10 half steps between the two notes.
  • The distance between the E and the Bb (the third and flatted seventh notes in the chord and the first and flatted fifth notes in an E major scale) is a diminished fifth (fig.3g). It contains five scale steps (E, F, G, A and B) and seven half steps between the two notes.

Fig.3

So a dominant seventh chord contains a:

  • Major third interval between the first and third notes.
  • Minor third interval between the third and fifth notes.   
  • Minor third interval between the fifth and flatted seventh notes. 
  • Perfect fifth interval between the first and fifth notes.
  • Minor seventh interval between the first and flatted seventh notes. 
  • Diminished fifth interval between the third and flatted seventh notes.   

Minor Seventh Chords

A minor seventh chord contains the first, flatted third, fifth and flatted seventh degrees of the major scale with the same root note. So a minor seventh chord contains six intervals: 

  • The distance between the first and flatted third notes.
  • The distance between the flatted third and fifth notes.
  • The distance between the fifth and flatted seventh notes.
  • The distance between the first and fifth notes.
  • The distance between the first and flatted seventh notes.
  • The distance between the flatted third and flatted seventh notes.

For example, a Cm7 chord (fig.4a) contains the notes C, Eb, G and Bb — the first, flatted third, fifth and flatted seventh notes in a C major scale. 

So a C7 chord contains six intervals:

  • The distance between the C and the Eb (the first and flatted third notes in a Cm chord and in a C major scale) is a minor third (fig.4b). It contains three scale steps (C, D and E) and three half steps between the two notes. 
  • The distance between the Eb and the G (the flatted third and fifth notes in the chord and the first and third notes in an Eb major scale) is a major third (fig.4c). It contains three scale steps (E, F and G) and four half steps between the two notes.
  • The distance between the G and the Bb (the fifth and flatted seventh notes in the chord and the first and flatted third notes in a G major scale) is a minor third (fig.4d).  It contains three scale steps (G, A and B) and three half steps between the two notes.
  • The distance between the C and the G (the first and fifth notes in the chord and in a C major scale) is a perfect fifth (fig.4e). It contains five scale steps (C, D. E, F and G) and and seven half steps between the two notes.
  • The distance between the C and the Bb (the first and flatted seventh notes in the chord and in a C major scale) is a minor seventh (fig.4f).  It contains seven scale steps (C, D, E, F, G, A and B) and 10 half steps between the two notes.
  • The distance between the Eb and the Bb (the flatted third and flatted seventh notes in the chord and the first and fifth notes in an Eb major scale) is a perfect fifth (fig.4g). It contains five scale steps (E, F, G, A and B) and seven half steps between the two notes.

Fig.4

So a minor seventh chord contains a:

  • Minor third interval between the first and flatted third notes.
  • Major third interval between the flatted third and fifth notes.   
  • Minor third interval between the fifth and flatted seventh notes.
  • Perfect fifth interval between the first and fifth notes.
  • Minor seventh interval between the first and flatted seventh notes. 
  • Perfect fifth interval between the flatted third and flatted seventh notes.   

Minor Seventh, Flat Five Chords

A minor seventh, flat five chord contains the first, flatted third, flatted fifth and flatted seventh degrees of the major scale with the same root note.  So a minor seventh, flat five chord contains six intervals: 

  • The distance between the first and flatted third notes.
  • The distance between the flatted third and flatted fifth notes.
  • The distance between the flatted fifth and flatted seventh notes.
  • The distance between the first and flatted fifth notes.
  • The distance between the first and flatted seventh notes.
  • The distance between the flatted third and flatted seventh notes.

For example, a Cm7(b5) chord (fig.5a) contains the notes C, Eb, Gb and Bb — the first, flatted third, flatted fifth and flatted seventh notes in a C major scale. 

So a Cm7(b5) chord contains six intervals: 

  • The distance between the C and the Eb (the first and flatted third notes in a Cm7(b5)  chord and in a C major scale) is a minor third (fig.5b). It contains three scale steps (C, E and G) and three half steps between the two notes. 
  • The distance between the Eb and the Gb (the flatted third and flatted fifth notes in the chord and the first and flatted third notes in an Eb major scale) is a minor third (fig.5c). It contains three scale steps (E, F and G) and three half steps between the two notes.
  • The distance between the Gb and the Bb (the flatted fifth and flatted seventh notes in the chord and the first and third notes in a Gb major scale) is a major third (fig.9d).  It contains three scale steps (G, A and B) and four half steps between the two notes.
  • The distance between the C and the Gb (the first and flatted fifth notes in the chord and in a C major scale) is a diminished fifth (fig.5e). It contains five scale steps (C, D, E, F and G) and six half steps between the two notes.
  • The distance between the C and the Bb (the first and flatted seventh notes in the chord and in a C major scale) is a minor seventh (fig.5f).  It contains seven scale steps (C, D, E, F, G, A and B) and 10 half steps between the two notes.
  • The distance between the Eb and the Bb (the flatted third and flatted seventh notes in the chord and the first and fifth notes in an Eb major scale) is a perfect fifth (fig.5g). It contains five scale steps (E, F, G, A and B) and seven half steps between the two notes.

Fig.5

So a minor seventh, flat five chord contains a:

  • Minor third interval between the first and flatted third notes.
  • Minor third interval between the flatted third and flatted fifth notes.   
  • Major third interval between the flatted fifth and flatted seventh notes. 
  • Diminished fifth interval between the first and flatted fifth notes.
  • Minor seventh interval between the first and flatted seventh notes. 
  • Perfect fifth interval between the flatted third and flatted seventh notes.   

Summary of Seventh Chord Interval Construction

Major Seventh Chords

A major seventh chord contains a:

  • Major third interval between the first and third notes.
  • Minor third interval between the third and fifth notes.   
  • Major third interval between the fifth and seventh notes. 
  • Perfect fifth interval between the first and fifth notes.
  • Major seventh interval between the first and seventh notes. 
  • Perfect fifth interval between the third and seventh notes.   

Dominant Seventh Chords

A dominant seventh chord contains a:

  • Major third interval between the first and third notes.
  • Minor third interval between the third and fifth notes.   
  • Minor third interval between the fifth and flatted seventh notes. 
  • Perfect fifth interval between the first and fifth notes.
  • Minor seventh interval between the first and flatted seventh notes. 
  • Diminished fifth interval between the third and flatted seventh notes.   

Minor Seventh Chords

A minor seventh chord contains a:

  • Minor third interval between the first and flatted third notes.
  • Major third interval between the flatted third and fifth notes.   
  • Minor third interval between the fifth and flatted seventh notes. 
  • Perfect fifth interval between the first and fifth notes.
  • Minor seventh interval between the first and flatted seventh notes. 
  • Perfect fifth interval between the flatted third and flatted seventh notes.  

Minor Seventh, Flat Five Chords

A minor seventh, flat five chord contains a:

  • Minor third interval between the first and flatted third notes.
  • Minor third interval between the flatted third and flatted fifth notes.   
  • Major third interval between the flatted fifth and flatted seventh notes. 
  • Diminished fifth interval between the first and flatted fifth notes.
  • Minor seventh interval between the first and flatted seventh notes. 
  • Perfect fifth interval between the flatted third and flatted seventh notes.   

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