Eleventh and Thirteenth Chords
Besides adding sevenths and ninths to triads, it is also possible to continue adding eleventh and thirteenth intervals. A triad to which the seventh, the ninth, the eleventh, and the thirteenth are added, will contain the seven notes of the scale:
Due to the sound density, one or more notes are usually eliminated from these chords. It is also common to eliminate the third, in particular in the case of eleventh chords. The following excerpt shows an example of these chords:
Gb Dominant 7th chord with 9th (Ab), 11th (Cb) and 13th (Eb)
C. Debussy, …La fille aux cheveux de lin
Recording by Robert Ståhlbrand. Read a complete analysis.