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A♭ minor 7th flat 5th chord on bass (A♭m7♭5)
Also called or written A♭m7♭5, A♭ or A♭ Half Diminished Minor 7
A♭ minor 7th flat 5th contains A♭, C♭, E♭♭ and G♭. The 4th-fret shape spreads four fingers across two frets, demanding a wide left-hand stretch.
How it is built
Formula 1, ♭3, ♭5, ♭7
- Root positionA♭–C♭–E♭♭–G♭A♭m7♭54-5-4-4
- First inversionC♭–E♭♭–G♭–A♭A♭m7♭5/C♭no shape on this instrument
- Second inversionE♭♭–G♭–A♭–C♭A♭m7♭5/E♭♭10-11-9-11
- Third inversionG♭–A♭–C♭–E♭♭A♭m7♭5/G♭2-2-0-1
How do you play an A♭ minor 7th flat 5th chord on bass?
A♭ minor 7th flat 5th is played at the 4th fret as 4 5 4 4: index finger on the E string at fret 4, pinky finger on the A string at fret 5, middle finger on the D string at fret 4 and ring finger on the G string at fret 4.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 4 | 1 | A♭ (1) |
| 3 (A) | 5 | 4 | E♭♭ (♭5) |
| 2 (D) | 4 | 2 | G♭ (♭7) |
| 1 (G) | 4 | 3 | C♭ (♭3) |
AdvancedThe wide stretch between the index finger on the 4th string and the pinky on the 3rd string at the 4th fret is the hardest part.
A♭m7♭5/E♭♭ inversion
A♭ minor 7th flat 5th is played at the 9th fret as 10 11 9 11: middle finger on the E string at fret 10, ring finger on the A string at fret 11, index finger on the D string at fret 9 and pinky finger on the G string at fret 11.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 10 | 2 | E♭♭ (♭5) |
| 3 (A) | 11 | 3 | A♭ (1) |
| 2 (D) | 9 | 1 | C♭ (♭3) |
| 1 (G) | 11 | 4 | G♭ (♭7) |
A♭m7♭5/G♭ inversion · open position
A♭ minor 7th flat 5th is played in open position as 2 2 0 1: middle finger on the E string at fret 2, ring finger on the A string at fret 2 and index finger on the G string at fret 1. The D string rings open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 2 | 2 | G♭ (♭7) |
| 3 (A) | 2 | 3 | C♭ (♭3) |
| 2 (D) | open | — | E♭♭ (♭5) |
| 1 (G) | 1 | 1 | A♭ (1) |
A♭m7♭5/G♭ inversion · fret 12
A♭ minor 7th flat 5th is played at the 12th fret as 14 14 12 13: ring finger on the E string at fret 14, pinky finger on the A string at fret 14, index finger on the D string at fret 12 and middle finger on the G string at fret 13.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 14 | 3 | G♭ (♭7) |
| 3 (A) | 14 | 4 | C♭ (♭3) |
| 2 (D) | 12 | 1 | E♭♭ (♭5) |
| 1 (G) | 13 | 2 | A♭ (1) |
Why it sounds like that
A♭ minor 7th flat 5th is built from the formula 1, ♭3, ♭5, ♭7. The diminished 5th between A♭ and E♭♭ gives the chord its tense, unresolved quality. Raising the ♭5 to a perfect 5th produces A♭ minor 7th, the closest stable contrast.
What goes wrong with A♭ minor 7th flat 5th?
- Letting the pinky collapse and mute the 2nd string.
- Fretting the 1st string with the ring finger too far from the fret, causing a buzz.
- Allowing the index finger to touch the 3rd string and deaden the A♭.
When to use it
A♭ minor 7th flat 5th functions as the ii chord in F♯ natural minor and the vii chord in A major. Use it in minor-key jazz and blues lines where the half-diminished colour leads to a dominant. It pairs naturally with A♭ minor and A♭ 5th.
Changing to and from A♭ minor 7th flat 5th
- Sliding the shape down one fret to the 3rd fret gives G minor 7th flat 5th.
- Sliding the shape up one fret to the 5th fret gives A minor 7th flat 5th.
Which voicing to use
The 4th-fret root position keeps A♭ in the bass for a grounded sound. The A♭m7♭5/D inversion at the 10th fret places the diminished 5th in the bass, creating a darker, less stable feel. Choose the A♭m7♭5/F♯ inversion when the bass line needs to descend to G♭.
Other A♭ chords
Common questions
How is A♭ minor 7th flat 5th written?
A♭ minor 7th flat 5th is written as A♭m7♭5, and it is also called Half Diminished Minor 7. The ASCII root spelling is Ab. It is also spelled G♯ in enharmonic notation for the same sounding root.
What is the difference between A♭ minor 7th flat 5th and A♭ diminished?
A♭ minor 7th flat 5th adds a minor 7th to the diminished triad. A♭ diminished has only the root, ♭3 and ♭5.
Why does A♭ minor 7th flat 5th sound unstable?
The tritone between A♭ and E♭♭ creates tension that wants to resolve. This instability makes the chord useful as a passing harmony.