Extended Tertian Harmony: 9th, 11th, and 13th Chords
Concept: By adding additional thirds to triadic harmony, one can create 9th, 11th, and 13th chords.
Note: It is common - and often necessary - to omit some notes of the chord, especially in four-part writing.
Examples:
Function: Most 9th, 11th, and 13th chords are dominant chords (V9, V11, V13), though in reality any triad can be extended. Other common non-dominant extended tertian chords are based on I and IV. Stacking extra thirds onto a triad does NOT change its original function! For instance, a V11 chord still typically resolves to I (or i), and a ii9 chord still typically resolves to dominant harmony (V).
Position: Extended tertian chords are usually found in root position, as they tend to lose their identity when inverted. Secondary function: 9th, 11th, and 13th chords can also occur as secondary dominants.
Analyze this progression:
Summary
Chord | Typical Members Present | Voice-Leading Guides |
---|---|---|
V9 | R, 3, 7, 9 | 9th and 7th resolve downward to the 5th and 3rd of the tonic triad. |
V11 | R, 3, 7, (9), 11 | 11th is retained as a common tone with the tonic triad. |
V13 | R, 3, 7, (9), 13 | 13th is usually in the highest voice and resolves downward to the tonic. If the tonic triad contains a chordal 9th, the 13th could resolve downward to the 9th of I9. |