Ab Half Diminished
Notes:Ab – B – D – Gb
Formula:R-m3-d5-m7
Intervals:P1-m3-d5-m7
Scale Degrees:1-b3-b5-b7
Introduction
The Ab Half Diminished piano chord (Abm7b5) consists of the notes Ab, B, D, Gb. It is a diminished triad with an added minor 7th, giving it a dark, moody, and tense character commonly used in jazz and minor key progressions. Formula: R-m3-d5-m7 | Scale degrees: 1-b3-b5-b7.
Enharmonic equivalent: A♭ is enharmonically equivalent to G♯. See G# Half Diminished.
Notes
Ab Half Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | Ab4 – B4 – D5 – Gb5 |
| 1st Inversion | B4 – D5 – Gb5 – Ab5 |
| 2nd Inversion | D5 – Gb5 – Ab5 – B5 |
| 3rd Inversion | Ab4 – B4 – D5 – Gb4 |
Key Signature
The key of Ab Half Diminished has 4 flats: B♭, E♭, A♭, D♭.
B♭E♭A♭D♭
Theory: Intervals
Formula: R-m3-d5-m7
Intervals: P1-m3-d5-m7
The Ab Half Diminished is built by stacking intervals from the root note. The formula R-m3-d5-m7 describes the scale degrees used. The intervals P1-m3-d5-m7 show the distance between each note in the chord.
Ab Half Diminished — Frequently Asked Questions
What notes are in the Ab Half Diminished chord?
Abm7b5 contains: Ab, Cb, Ebb, Gb. Diminished triad with minor seventh.
How does Abm7b5 differ from Abdim7?
Minor seventh (Gb) vs diminished seventh (Gbb/F).
How is Abm7b5 used?
ii chord in Gb minor.
What songs use Half Diminished?
Jazz minor-key harmony.
How does Abm7b5 differ from Abm7?
Flatted fifth (Ebb vs Eb).
Is Abm7b5 the same as Cbm6?
Same notes, different root.
Practice Tips
- Minor-key ii–V–i: Abm7b5 → Db7 → Gbm.
- Abm7b5 and Cbm6 same notes.
- Compare with Abdim7.
- Jazz vocabulary.
- Mostly black keys.
- The flatted fifth creates tension.