Seventh chords
Music theory · Chords · Level 3 · 14 min
Add one more third on top of a triad and you get a seventh chord: four notes, root – third – fifth – seventh. It's the king of jazz chords, but also the engine of classical harmony.
The five essential types
| Name | Construction | On C | Symbol |
|---|---|---|---|
| Major seventh | major triad + major 7th | C – E – G – B | Cmaj7, CΔ, CM7 |
| Dominant seventh | major triad + minor 7th | C – E – G – B♭ | C7 |
| Minor seventh | minor triad + minor 7th | C – E♭ – G – B♭ | Cm7, C-7 |
| Half-diminished | diminished triad + minor 7th | C – E♭ – G♭ – B♭ | Cm7♭5, Cø |
| Diminished seventh | diminished triad + diminished 7th | C – E♭ – G♭ – B𝄫 | C°7, Cdim7 |
M:4/4 L:1/2 K:C "Cmaj7"[CEGB]2 | "C7"[CEG_B]2 | "Cm7"[C_EG_B]2 | "Cm7b5"[C_E_G_B]2 | "Cdim7"[C_E_G__B]2 |]
Listen to them one by one and attach an image to each: the dreamy major seventh, the dominant seventh straining toward resolution, the soft, mellow minor seventh, the uneasy half-diminished, the dramatic diminished seventh (the silent-movie chord for when the villain walks in!).
The dominant seventh and its resolution
Built on the 5th degree (G7 in C major), this chord contains a tritone between its third (B) and its seventh (F). That tritone resolves naturally: B rises to C, F falls to E. It is the strongest pull in all of tonal music.
M:4/4
L:1/2
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
K:C
[V:RH] "G7"[FB]2 | "C"[Ec]2 |]
[V:LH] [G,,G,]2 | [C,C]2 |]
Sevenths on the C major scale
On each degree of C major (white keys only): Cmaj7, Dm7, Em7, Fmaj7, G7, Am7, Bm7♭5. There is only one dominant seventh per major key: the one on the 5th degree.
Inverting seventh chords
With four notes there are three inversions. The figures are 7 (root position), 6/5 (first inversion), 4/3 (second), 4/2 or 2 (third, seventh in the bass). French tradition uses its own symbols for the dominant seventh (7/+, 6/5 with a slashed 5, +6, +4, where + marks the leading tone) — useful to know if you read French textbooks.