A flat Diminished Chord (A♭dim)

1Composition: what it contains

A♭ – C♭ – E𝄫

Symbol

A♭dim

Also written

A♭dim, A♭°, A♭m♭5, A♭mi(♭5)

Formula

1 ♭3 ♭5

Same sound as

G♯dim

2Appearance: diagrams and sound

On the guitar

On the ukulele

On the piano

On the staff

On bass and as an arpeggio

3Indications: what it is used for

The vii° chord of a major key and the ii° chord of a minor key are diminished triads. It works as a leading-tone chord resolving to the tonic (vii°–I), as a passing chord between two diatonic chords (for example between I and ii, or IV and V), and as an incomplete dominant seventh: the vii° triad contains the 3, 5 and 7 of V7. Classical, jazz, gospel and film music use it for tension and chromatic movement in the bass.

4Dosage: how to practise it

On piano, play the triad in all inversions at 60 BPM, then practise vii°6–I resolutions with smooth voice leading (the diminished fifth contracting to a third). On guitar, learn the compact three-string shapes on the top strings and the shape rooted on the fifth string. Practise the passing progression I–♯I°–ii–V slowly, then at 80–100 BPM. Arpeggiate 1-♭3-♭5 on bass. Five minutes a day is enough once the shapes are known.

5Warnings and common mistakes

Do not confuse the triad (dim) with the diminished seventh chord (dim7 or °7) or the half-diminished seventh (m7♭5 or ø7): many charts write 'dim' when they mean the four-note dim7, so check the style. The diminished fifth is not a perfect fifth; on guitar, power-chord habits make players play the wrong fifth. In root position the triad can sound harsh; first inversion is the most common classical voicing.

6Interactions with chords, scales and keys

Inversions

• Inversion 1 · A♭dim/C♭ · C♭ – E𝄫 – A♭ Play
• Inversion 2 · A♭dim/E𝄫 · E𝄫 – A♭ – C♭ Play

Scales to play over A♭dim

• G sharp Locrian Mode
• G sharp Blues Scale
• A flat Half-Whole Diminished Scale
• G sharp Whole-Half Diminished Scale
• A flat Hungarian Minor Scale
• G sharp Altered Scale

Where it appears (keys and Roman numerals)

• vii° – Key of A Major
• ii° – Key of F sharp Minor

7Other presentations available

The same chord from every note

Cdim C♯dim Ddim E♭dim Edim Fdim F♯dim Gdim Adim B♭dim Bdim

Other chords on A♭

A♭ A♭m A♭aug A♭sus2 A♭sus4 A♭5 A♭6 A♭m6 A♭7 A♭maj7 A♭m7 A♭m7♭5 A♭dim7 A♭m(maj7) A♭7sus4 A♭add9 A♭m(add9) A♭6/9 A♭9 A♭maj9 A♭m9 A♭11 A♭m11 A♭13 A♭7♭9 A♭7♯9 A♭7♯5 A♭7♭5