A♭ diminished major 7th chord on guitar (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 is built from A♭, C♭, E♭♭ and G. The 4th fret shape mutes the B string, which is a chord tone here.

4frA♭E♭♭GC♭EADGBE
Positions on the neck1 of 5
Practice A♭ diminished major 7th chord

How it is built

A♭RootC♭Minor thirdE♭♭Diminished fifthGMajor seventh

Formula 1, ♭3, ♭5, 7

Inversions

How do you play an A♭ diminished major 7th chord on guitar?

A♭ diminished major 7th is played at the 4th fret as 4 5 5 4 × ×: index finger on the low 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. The B and high e strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)41A♭ (1)
5 (A)53E♭♭ (♭5)
4 (D)54G (7)
3 (G)42C♭ (♭3)
2 (B)muted
1 (e)muted

AdvancedThe pinky on the D string at fret 5 must arch over the ring finger on the A string, while the B string stays muted despite being a chord tone.

6th fret

A♭ diminished major 7th is played at the 6th fret as × × 6 7 8 7: index finger on the D string at fret 6, middle finger on the G string at fret 7, pinky finger on the B string at fret 8 and ring finger on the high e string at fret 7. The low E and A strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)muted
4 (D)61A♭ (1)
3 (G)72E♭♭ (♭5)
2 (B)84G (7)
1 (e)73C♭ (♭3)

11th fret

A♭ diminished major 7th is played at the 11th fret as × 11 12 12 12 ×: index finger on the A string at fret 11, middle finger on the D string at fret 12, ring finger on the G string at fret 12 and pinky finger on the B string at fret 12. The low E and high e strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)111A♭ (1)
4 (D)122E♭♭ (♭5)
3 (G)123G (7)
2 (B)124C♭ (♭3)
1 (e)muted

A♭dimM7/C♭ inversion · ×-2-0-1-0-3

A♭ diminished major 7th is played in open position as × 2 0 1 0 3: middle finger on the A string at fret 2, index finger on the G string at fret 1 and ring finger on the high e string at fret 3. The D and B strings ring open. The low E string stays muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)22C♭ (♭3)
4 (D)openE♭♭ (♭5)
3 (G)11A♭ (1)
2 (B)openC♭ (♭3)
1 (e)33G (7)

A♭dimM7/C♭ inversion · ×-2-0-1-3-3

A♭ diminished major 7th is played in open position as × 2 0 1 3 3: middle finger on the A string at fret 2, index finger on the G string at fret 1, ring finger on the B string at fret 3 and pinky finger on the high e string at fret 3. The D string rings open. The low E string stays muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)22C♭ (♭3)
4 (D)openE♭♭ (♭5)
3 (G)11A♭ (1)
2 (B)33E♭♭ (♭5)
1 (e)34G (7)

Why it sounds like that

A♭ diminished major 7th uses the formula 1, ♭3, ♭5, 7. The diminished 5th between A♭ and E♭♭ creates a tritone, and the major 7th G is the leading tone. Compare it to A♭ minor 7th flat 5th, which lowers the 7th to G♭.

What goes wrong with A♭ diminished major 7th?

  • Letting the B string ring open and doubling the ♭3.
  • Flattening the pinky onto the G string and muting the ♭5.

When to use it

A♭ diminished major 7th appears in A♭ minor progressions as a passing chord, often moving to A♭ minor or A♭ major 7th. The leading tone G pulls to A♭, so use it before an A♭ major cadence. It suits dark jazz and classical tension.

Changing to and from A♭ diminished major 7th

  • Sliding the shape down one fret to the 3rd fret gives G diminished major 7th.

Which voicing to use

The 4th fret shape keeps the bass on A♭ and is the default. The 6th fret shape repeats the voicing an octave higher, while the 11th fret adds a brighter register for solos.

Other A♭ chords

Common questions

How is A♭ diminished major 7th written?

A♭ diminished major 7th is written A♭°M7 or A♭dimM7. 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♭ diminished major 7th and A♭ minor 7th flat 5th?

A♭ diminished major 7th has a major 7th, G. A♭ minor 7th flat 5th lowers that note to G♭, giving a dominant-quality chord.

Why does A♭ diminished major 7th sound so unstable?

The diminished 5th between A♭ and E♭♭ creates a tritone, and the major 7th G sits a semitone below the octave. Both intervals demand resolution.