Discussion 3b - Seventh Chords

Class Discussion

Lowest pitch=bass. Root is the chord that be build the thirds around.

How do we determine seventh chord quality?

The first letter gives the quality of the triad, while the second letter gives the quality of the seventh. For example, Mm7 = a major triad + a minor seventh.

Looking at both the triads in the seventh chord and be aware of the different qualities they have.

Dominant and Dimished relationship: They both have diminished 5ths. Dominant is between 3rd and 7th, while diminished is 1st and 5th (all chordal pitches).

How do we determine and label seventh chord inversions?

Seventh chords add third inversion because they have an additional note compared to triads. Their inversion figures are as such:

• Root position: 7
• First inversion: 6/5
• Second inversion: 4/3
• Third inversion: 4/2

Remember to not add the slash when handwriting. Stacked things are just impossible to notate online.

The inversions figures do not tell you the exact intervals and their qualities above the bass. These are made to work with roman numberals.

Further Reading

From Open Music Theory

Seventh chords

A four-note chord whose pitch classes can be arranged as thirds is called a seventh chord.

Like with a triad, the pitch classes belonging to a seventh chord occupy adjacent positions (a four-pitch-class clump) on the circle of thirds. The four members of a seventh chord are the root, third, fifth, and seventh.

There are five qualities of seventh chords that appear in diatonic music: major seventh, dominant seventh, minor seventh, diminished seventh (also called fully-diminished), and half-diminished seventh. They are comprised of the following intervals above their roots:

• major seventh: M3, P5, and M7 above the root (or major triad with a major seventh)
• dominant seventh: M3, P5, and m7 above the root (or major triad with a minor seventh)
• minor seventh: m3, P5, and m7 above the root (or minor triad with a minor seventh)
• diminished seventh: m3, d5, and d7 above the root (or diminished triad with a diminished seventh)
• half-diminished seventh: m3, d5, and m7 above the root (or diminished triad with a minor seventh)

Following are the lead-sheet abbreviations for seventh-chord qualities:

• major seventh: maj7 or △7 (G^maj7 or G^△7)
• dominant seventh: 7 (B⁷)
• minor seventh: m7 (F♯^m7)
• diminished seventh: dim7 or °7 (D^dim7 or D^°7)
• half-diminished seventh: ⦰7 (A^⦰7)