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Page 18

Dominant Seventh Chords
A different type of chord can be created by adding another note to a triad. This note is often identified by a number
that indicates its scale degree.
Here is the scale of C major:

1 2 3 4 5 6 7

C D E F G A B

The triad of C major (chord I) is made by putting together the notes C, E and G (1-3-5). The dominant seventh chord
is formed by adding the note one tone (one full step) below the root: C major C E G becomes C E G Bb. It is called
the "dominant" seventh because in traditional harmony the fifth note of the scale (the dominant) is the only one on
which a dominant seventh chord will occur if you build a chord upon it. In the key of C, for example, G is the
dominant; G dominant seventh is G B D F. Notice that the fourth note of the chord, F, is one full step below the root,
G.
In the blues, however, a dominant seventh chord can occur on chord I or chord IV as well as chord V, and in popular
music the seventh note of the scale is often flattened.
The chords of A7, B7, C7, D7, E7 and G7 can be played in first position as open-string shapes.
The dominant seventh chord has a hard, bluesy sound. Use it to toughen up a chord sequence, as it does in songs
such as 'Caught By The Fuzz', 'When I Get Home', 'Baby's In Black' and 'Hard Day's Night'. It is also used to
establish a new key – there is more about this in section ten on key-changing.

Dominant seventh chord shapes