Jazz music frequently employs extended and altered chords to add color, complexity, and emotional depth to harmony. Extended chords go beyond the basic triad or seventh, incorporating tones like the 9th, 11th, and 13th, which produce richer and more textured sounds. Altered chords modify standard tones with sharp or flat alterations (such as b9, #9, #11, b13), injecting tension and dissonance that jazz musicians cleverly resolve for dramatic effect.
- Extended chords add tones beyond the octave for richer sounds.
- Altered chords introduce non-diatonic tones for tension.
- Both types create harmonic interest and smooth chord transitions.
Extended chords add tones beyond the triad/seventh like 9ths, 11ths, and 13ths.
Altered chords create harmonic tension through dissonant tones.
Extended Chords
Extended chords build on basic triads and sevenths by including additional scale degrees:
- 9th chord: Adds the 9th (2nd octave) to a seventh chord (Cmaj7 → Cmaj9: C-E-G-B-D).
- 11th chord: Adds the 11th (perfect fourth above the 7th) (Cmaj9 → Cmaj11: C-E-G-B-D-F).
- 13th chord: Adds the 13th (major 6th above the 7th) (Cmaj11 → Cmaj13: C-E-G-B-D-F-A).
These chords produce “vertical” harmonic stacking, making the sound lush and open-ended — ideal for jazz’s fluid textures.
A C13 chord includes root, 3rd, 5th, 7th, 9th, 11th, and 13th: C, E, G, Bb, D, F, A.
Extended chords are characterized by the addition of 9th, 11th, and 13th.
Altered Chords
Altered chords tweak dominant chords by sharpening or flattening their usual extensions, resulting in powerful tension often used before resolution.
- b9 and #9: A minor or major 9th placed above the root in a dominant chord (e.g. G7b9, G7#9).
- #11: A raised 11th adds a distinct dissonance (e.g. C7#11).
- b13: A lowered 13th replaces the typical 13th for more edge (e.g. A7b13).
These alterations are typically found on dominant (V7) chords, providing a springboard for creative improvisation and smooth modulations.
An altered dominant chord might be G7 with b9, #9, or b13, such as G7b9#13.
Altered dominant chords commonly use b9, #9, #11, and b13.
Examples in Context
| Chord Type | Example | Notes (C Root) | Description |
|---|---|---|---|
| Extended | Cmaj9 | C-E-G-B-D | Adds 9th, for richness |
| Extended | C13 | C-E-G-Bb-D-F-A | Adds up to 13th, very full |
| Altered | C7b9 | C-E-G-Bb-Db | Adds tension with b9 |
| Altered | C7#9#11 | C-E-G-Bb-D#-F# | Very tense, for dramatic effect |
9th, 11th, and 13th are common extensions in jazz chords.
Alterations like b9, #9, b13, and #11 are typical in altered dominants.
Conclusion
Extended chords add lushness and sophistication with extra tones, while altered chords deliver dynamic tension and release—both are key to jazz’s distinctive harmonic language.
- Extended chords use 9ths, 11ths, and 13ths for richer color.
- Altered chords modify tones to create tension and forward motion.
- Mastery of these chords unlocks new expressive possibilities in jazz music.