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Jazz blues has evolved significantly since its origins, incorporating complex harmonic techniques that enrich its sound. One of the most influential developments in modern jazz blues harmony is the use of altered chords. These chords introduce dissonance and tension, creating a more expressive and sophisticated harmonic palette.
Understanding Altered Chords in Jazz Blues
Altered chords are chords that contain altered tones—notes that are raised or lowered by a semitone relative to their standard pitch. Common alterations include flat or sharp ninths, elevenths, and thirteenths. These chords are often built on the dominant seventh, adding a layer of tension that seeks resolution.
Common Altered Chords Used in Jazz Blues
- 7#9: A dominant seventh chord with a raised ninth, e.g., G7#9.
- 7b9: A dominant seventh with a lowered ninth, e.g., G7b9.
- 7#11: A dominant seventh with a raised eleventh, e.g., G7#11.
- 7b13: A dominant seventh with a lowered thirteenth, e.g., G7b13.
Incorporating Altered Chords into Jazz Blues Progressions
Altered chords are typically used on the V7 chord in a blues progression, especially before resolving to the I chord. For example, in a 12-bar blues in C, the V7 chord (G7) can be replaced with G7#9 or G7b9 to add color and tension.
Here’s an example of a jazz blues progression with altered chords:
C7 | F7 | C7 | C7
F7 | F7 | C7 | A7b9
D7 | G7#9 | C7 | G7
Voice Leading and Resolution
Effective use of altered chords requires smooth voice leading. The dissonant tones in altered chords typically resolve stepwise to more stable tones. For example, the #9 in G7#9 often resolves downward to the 3rd (B) of the C major chord, creating a satisfying resolution.
Listening Examples and Practice
Listening to recordings of jazz legends like Charlie Parker or Miles Davis can provide insight into the use of altered chords. Transcribing solos and chord voicings helps students internalize these harmonic techniques.
Conclusion
Incorporating altered chords into jazz blues adds emotional depth and harmonic complexity. Mastery of these chords enhances improvisational skills and enriches the overall musical expression. As jazz continues to evolve, the creative use of altered harmonies remains a vital part of modern jazz vocabulary.