As eleventh (v. Lat. Undecimus "the eleventh") is referred to in the music an interval , which is composed of octave and fourth composed and eleven pitches of a diatonic , heptatonic scale spans (eg. C-f 1 ). The frequency ratio between a pure undecimal and its fundamental is 8/3.
Note example: undecimal intervals
The (pure) undecimal (a) comprises seventeen semitones. In counterpoint and harmonic movement, undecimals are usually treated like fourths.
In the jazz harmonic , the undezime plays a special role as the fifth third above the root note (b); it is numbered with “11” in the chord symbolism.
In connection with the partial tones , e.g. B. in organ registers , the 11th partial is called the undezime. This undecimal has a frequency ratio of 11: 8 to the next lower octave.