Perfect Eleventh
Definition & Properties
The perfect eleventh is a compound interval spanning an octave plus a perfect fourth. It creates an open, suspended quality in extended chord voicings and is a staple of jazz orchestration.
| Property | Value |
|---|---|
| Abbreviation | P11 |
| Semitones | 17 |
| Quality | Perfect |
| Just Ratio | 8:3 |
| Cents from Equal | -1.96 |
| Harmonic Character | open suspension |
Ear Training Reference
The Perfect Eleventh (P11) is commonly recognized by the ascending motion of: Compound perfect fourth; sus4 chord extension.
Practice direction: ascending — sing from the lower note up by 17 semitones.
Note Pair Examples
| Note 1 | Note 2 | Interval | Semitones |
|---|---|---|---|
| C | F (+ octave) | Perfect Eleventh | 17 |
| G | C (+ octave) | Perfect Eleventh | 17 |
| D | G (+ octave) | Perfect Eleventh | 17 |
| F | A# (+ octave) | Perfect Eleventh | 17 |
Intonation by Temperament
The Perfect Eleventh measures 8:3 in just intonation (-1.96 cents from equal temperament). This deviation affects ensemble tuning and instrument voicing.
| Temperament | C4 (Hz) | F5 (Hz) |
|---|---|---|
| Equal Temperament | 261.626 | 698.456 |
| Pythagorean | 260.740 | 695.309 |
| Just Intonation | 261.626 | 697.668 |
Instrument Tuning Context
Compound intervals (17 semitones) span more than an octave and appear in extended harmony and orchestral voicings.
Chords & Scales Containing This Interval
Chords
These chord types contain the Perfect Eleventh as a characteristic interval:
Scales
These scales include the Perfect Eleventh as a structural interval: