Discussion 3b - Seventh Chords

Class Discussion

TBD

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)