Dominant Seventh Chord
A major chord with a flattened seventh on top, and the most impatient sound in Western music. Two of its four notes are a tritone apart, and that interval is why the chord will not sit still.
- 4 notes
- 1 3 5 b7
- wants to move
which styles use it
- Blues
- Rock & folk
- Jazz
- Gospel
Which notes are in a dominant seventh?
A major triad with a fourth note ten half steps above the root, which is one half step lower than the seventh of the major scale. In C that means a B flat and not a B.
The interval between the third and that flattened seventh is six half steps, the tritone, and it is the most restless distance in the system. In C the four notes are C, E, G and B flat.
- C, the root
- E, the major third
- G, the fifth
- B flat, the minor seventh
Where does it want to go?
Down a fifth, almost every time. C7 leans toward F, G7 leans toward C. The tritone resolves by squeezing inward: the third climbs a half step, the seventh drops one, and both land on notes of the next chord. What changes per style is whether that landing is allowed to happen at all.
The plainest version there is. The V7 arrives, everything leans, and the next chord catches it. Stop on the V7 and you can feel how badly it wants that last bar.
When do you reach for it?
- As the V7, the last chord before you come home. This is its day job.
- All over blues and rock, where the I and the IV are dominant sevenths too and nothing ever fully resolves.
- As a secondary dominant, pointing at a chord other than the tonic to give one bar a sudden sense of direction.
How do you spot one in a key?
Stack four thirds on every degree of a major scale and you get Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7b5. Exactly one dominant seventh in the row, on the fifth degree.
That is why this chord announces a key so strongly. Hear a G7 anywhere and your ear expects C, because there is only one major key in which a G7 occurs naturally. It is also why blues sounds the way it does: put dominant sevenths on the first and the fourth degree as well and no single key can account for them, so nothing ever fully settles.
Which of the three do you actually want?
All three sit on the same root and differ by a single note. That one note decides whether the chord asks a question, answers it, or stays out of the way. Play them back to back before you read the reasons.
Common mistakes
- Using it as a resting chord
Outside blues, ending a section on a dominant seventh leaves the listener hanging. Sometimes that is the point. Know which one you are doing.
- Mixing it up with maj7
One note separates them and they behave in opposite ways. Maj7 floats, dominant seventh pulls.
Keep going
Everything in chords
- Major Seventh Chord
- Dominant Seventh Chord
- Minor Seventh Chord
- Diminished Seventh Chord
- Minor Major Seventh Chord