Bb Half Diminished
Notes:Bb – Db – E – Ab
Formula:R-m3-d5-m7
Intervals:P1-m3-d5-m7
Scale Degrees:1-b3-b5-b7
Introduction
The Bb Half Diminished piano chord (Bbm7b5) consists of the notes Bb, Db, E, Ab. 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: B♭ is enharmonically equivalent to A♯. See A# Half Diminished.
Notes
Bb Half Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | Bb4 – Db5 – E5 – Ab5 |
| 1st Inversion | Db5 – E5 – Ab5 – Bb5 |
| 2nd Inversion | E5 – Ab5 – Bb5 – Db6 |
| 3rd Inversion | Bb4 – Db5 – E5 – Ab4 |
Key Signature
The key of Bb Half Diminished has 2 flats: B♭, E♭.
B♭E♭
Theory: Intervals
Formula: R-m3-d5-m7
Intervals: P1-m3-d5-m7
The Bb 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.
Bb Half Diminished — Frequently Asked Questions
What notes are in the Bb Half Diminished chord?
Bbm7b5 contains: Bb, Db, Fb, Ab. Diminished triad with minor seventh.
How does Bbm7b5 differ from Bbdim7?
Minor seventh (Ab) vs diminished seventh (Abb/G).
How is Bbm7b5 used?
ii chord in Ab minor.
What songs use Half Diminished?
Jazz minor-key harmony.
How does Bbm7b5 differ from Bbm7?
Flatted fifth (Fb vs F).
Is Bbm7b5 the same as Dbm6?
Same notes, different root.
Practice Tips
- Minor-key ii–V–i: Bbm7b5 → Eb7 → Abm.
- Bbm7b5 and Dbm6 same notes.
- Compare with Bbdim7 and Bbm7.
- Jazz vocabulary.
- All flats.
- The Fb creates tension.