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A♭ diminished major 7th chord on bass (A♭dimMaj7)
Also called or written A♭dimMaj7, A♭dimM7, A♭°M7, A♭ augmented minor seventh or A♭ minor seventh sharp five
A♭ diminished major 7th contains A♭, C♭, E♭♭, and G. The 4th-fret shape is movable, and an easier inversion at the 1st fret uses an open D string.
How it is built
Formula 1, ♭3, ♭5, 7
How do you play an A♭ diminished major 7th chord on bass?
A♭ diminished major 7th is played at the 4th fret as 4 5 5 4: index finger on the E string at fret 4, ring finger on the A string at fret 5, pinky finger on the D string at fret 5 and middle 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 | 3 | E♭♭ (♭5) |
| 2 (D) | 5 | 4 | G (7) |
| 1 (G) | 4 | 2 | C♭ (♭3) |
AdvancedA♭ diminished major 7th requires the ring finger and pinky to fret adjacent strings at the same fret while the index and middle hold the lower fret.
A♭dimM7/G inversion
A♭ diminished major 7th is played in open position as 3 2 0 1: ring finger on the E string at fret 3, middle 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) | 3 | 3 | G (7) |
| 3 (A) | 2 | 2 | C♭ (♭3) |
| 2 (D) | open | — | E♭♭ (♭5) |
| 1 (G) | 1 | 1 | A♭ (1) |
Why it sounds like that
A♭ diminished major 7th is built from the formula 1, ♭3, ♭5, 7. The diminished 5th between A♭ and E♭♭ creates a tritone that gives the chord its dark color. The major 7th G is a leading tone that resolves upward to A♭. Compare with A♭ minor 7th flat 5th, which has G♭ instead of G.
What goes wrong with A♭ diminished major 7th?
- Letting the ring finger mute the 2nd string, which silences the C♭.
- Pressing the pinky too lightly, causing the 2nd string to buzz.
- Allowing the index finger to drift sharp, making the 4th string note out of tune.
When to use it
A♭ diminished major 7th works as a passing chord in A♭ minor, often between A♭ minor and A♭ minor 7th. Its tense sound suits jazz ballads and dramatic film cues. Use it to add chromatic motion on the bass.
Changing to and from A♭ diminished major 7th
- Sliding the shape down two frets to the 2nd fret gives F♯ diminished major 7th.
- Sliding the shape up one fret to the 5th fret gives A diminished major 7th.
Which voicing to use
The 4th-fret position places the root A♭ on the 4th string, giving a solid low foundation. The A♭dimM7/F♯♯ inversion at the 1st fret puts G in the bass, creating a different color while keeping the same notes.
Other A♭ chords
Common questions
How is A♭ diminished major 7th written?
A♭ diminished major 7th is written A♭°M7 or A♭dimM7. The root is A♭, with ASCII spelling Ab. It is also spelled G♯ in enharmonic notation for the same sounding root.
What is the difference between A♭ diminished major 7th and A♭ minor 7th flat 5th?
A♭ diminished major 7th has a major 7th (G), while A♭ minor 7th flat 5th has a minor 7th (G♭). The major 7th creates a leading tone that pulls strongly to the octave.
Which inversion of A♭ diminished major 7th is easier for beginners?
The A♭dimM7/F♯♯ inversion at the 1st fret is easier because it uses an open D string and lower frets. However, the root position is more common for moving up the neck.