Dominant 7th chords

Add a 4th note to a chord and it gets richer. The DOMINANT 7TH is a major triad plus a MINOR 7th on top: 1, 3, 5, ♭7.

Written as just "7": C7, G7. This is the engine of blues (all three chords in a 12-bar blues are dominant 7ths) and the chord that pulls hardest back to its home key in any song.

To build it: play the major chord, then add the note a whole tone below the root's octave. C major + B♭ = C7.

1 · 3 · 5 · ♭7 (major triad + minor 7th)

C7: C–E–G–B♭.

Practise this in the trainer — it opens with this lesson the first time the concept comes up.