7th chords are an essential aspect of jazz music because they provide additional color and richness to harmonies. The 7th chord is a four-note chord that includes the root note, the third note, the fifth note, and the seventh note of the scale. The seventh note is the note that distinguishes it from a triad, which has only three notes.
The use of 7th chords in jazz music provides a more complex and sophisticated sound. Jazz musicians frequently use chord progressions that include 7th chords to create a sense of tension and release. For example, the ii-V-I progression, which is a common jazz chord progression, includes three 7th chords: the ii chord, which is a minor 7th chord, the V chord, which is a dominant 7th chord, and the I chord, which is a major 7th chord.
The use of 7th chords in jazz music also allows for greater improvisation. Jazz musicians often use 7th chords as a framework for improvisation. They can use the notes in the chord to create melodic lines or explore different harmonies by adding or subtracting notes.
In addition, the use of 7th chords in jazz music is rooted in the history of jazz. During the early years of jazz, musicians frequently played in small ensembles, and the use of 7th chords allowed them to create a fuller sound with fewer instruments. As jazz music evolved and big bands became more popular, the use of 7th chords remained an essential aspect of jazz harmonies.
Sources:
- Bertrand, M. (2013). Jazz Theory Handbook. Mel Bay Publications.
- Levine, M. (1995). The Jazz Theory Book. Sher Music Co.
