Audio: seventh chord (0:10)
|USE IN HARMONY
|SEVENTH CHORD NAME
|Major and minor
|minor major seventh
|augmented major seventh
seventh chord demonstrates seventh chords played by a jazz quartet comprising soprano sax, alto sax, tenor sax and baritone sax. The seventh chord figure shows the score and the table lists the eight different types of seventh chord that are used in the piece:
A seventh chord contains four different notes. It is a tertian chord constructed from a root note using intervals of thirds.
Jazz harmony is based on the seventh chord.
The seventh chord is not exclusive to jazz harmony. Functional and pop harmony both use the dominant seventh chord and the major and minor seventh chords. The difference between jazz harmony and the other approaches to harmony is that jazz harmony is based on the seventh chord whereas functional harmony is based on the triad whilst pop harmony uses any chord that is available.
There are eight different types of seventh chord. Seven of the eight are constructed from the notes in a major scale or a minor scale. The odd one out is the augmented seventh. It is not constructed from three consecutive major thirds because that will result in an augmented triad with a doubled note. Instead, it is an artificial chord, the last of the major thirds is halved from four to two semitones to produce an augmented seventh chord.
Four of the seventh chords are widely used in jazz major harmony, and are listed in the seventh chord table. They are the major seventh, dominant seventh, minor seventh and half-diminished seventh chords. These four chords, together with the major sixth chord, are sufficient to write a lot of interesting jazz harmony in a major key.
Things are more complicated in a minor key, as usual. There is the perennial issue of which minor scale to use. The seventh chord table lists seventh chords constructed from the harmonic minor scale. They include the four chords that are also used in major harmony. In addition, the diminished seventh chord and minor major seventh are available, together with the augmented major seventh, which some jazzers consider a diatonic chord while others treat it, and any chord containing an augmented fifth, as a chromatic or altered chord.
Sometimes you will see references in the literature to a jazz chord and a jazz scale. These are not special chords or scales but generic terms for any chord and scale used in jazz. Similarly, the jazz minor scale sounds like a new scale when it is actually the ascending version of the melodic minor scale. Jazz minor harmony uses the jazz minor scale sometimes instead of the harmonic minor scale, for example, a ii7 to replace the ii7b5. The aeolian mode can also be thrown into the mix with an i7 replacing iminmaj7 for example. Chuck in the minor sixth chord as well and you will never be short of options in jazz minor harmony.
A seventh chord contains all the intervals. A root position seventh chord includes the intervals of third, fifth and seventh, inversions include the intervals of sixth, fourth and second. That is the lot. There are no more intervals left. The same is true of any chord with four notes. The seventh chord and the add chord, including the major sixth chord, together with their inversions, contain all possible intervals.
One thing that may put music writers off writing jazz harmony is the complexity of the notation. Jazz harmony notation is truly amazing. Amazing, as in, be prepared to get stuck in a maze. To make matters worse, there are various ways to notate a chord. The seventh chord table is as good a list as any and these chord names and symbols are used throughout the guide.