Ab Half-Diminished Seventh (Minor 7♭5)
Chord Tones: Ab Half-Diminished Seventh (Minor 7♭5)
Symbol: ø7, m7♭5 — Formula: 1-♭3-♭5-♭7
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | Ab | 415.305 Hz |
| ♭3 | B | 493.883 Hz |
| ♭5 | D | 293.665 Hz |
| ♭7 | Gb | 369.994 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Abø7 |
| All Common Symbols | ø7, m7♭5 |
| Interval Formula | 1-♭3-♭5-♭7 |
| Harmonic Category | dissonant |
Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.
Inversions
| Inversion | Notes (low to high) | Bass Note | Slash Notation |
|---|---|---|---|
| Root Position | Ab – B – D – Gb | Ab | Ab Half-Diminished Seventh (Minor 7♭5) |
| First Inversion | B – D – Gb – Ab | B | Ab Half-Diminished Seventh (Minor 7♭5)/B |
| Second Inversion | D – Gb – Ab – B | D | Ab Half-Diminished Seventh (Minor 7♭5)/D |
| Third Inversion | Gb – Ab – B – D | Gb | Ab Half-Diminished Seventh (Minor 7♭5)/Gb |
Harmonic Function
The Ab half diminished chord commonly functions as the submediant (♭VI) in C minor or subdominant in E♭ major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.
The half-diminished chord (minor seven flat five) combines a diminished triad with a minor seventh. It is the ii chord in minor keys and an essential sound in jazz and classical harmony.
Common Progressions
The Ab Half-Diminished Seventh (Minor 7♭5) frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
iiø-V7-iviiø-I
Songs Featuring the Half-Diminished Seventh (Minor 7♭5)
Well-known songs where the Ab Half-Diminished Seventh (Minor 7♭5) — or this chord type — plays a prominent role:
- Autumn Leaves (minor ii chord) – jazz standard
- Beautiful Love – jazz standard
- Solar – Miles Davis
Tuning Frequencies Across Temperaments
Frequencies shown at A=440 Hz. View full temperament data for any note.
| Note | Equal Temp. | Pythagorean | Just Intonation |
|---|---|---|---|
| Ab | 415.305 Hz | 417.657 Hz | 418.601 Hz |
| B | 493.883 Hz | 495.000 Hz | 490.548 Hz |
| D | 293.665 Hz | 293.332 Hz | 294.329 Hz |
| Gb | 369.994 Hz | 371.251 Hz | 367.911 Hz |
Scales Containing the Ab Half-Diminished Seventh (Minor 7♭5)
These scales include the Ab Half-Diminished Seventh (Minor 7♭5) as a diatonic or characteristic chord: