# A♭ Diminished 7th piano chord (A♭dim7) A♭dim7 contains A♭, C♭, E♭♭ and G♭♭. Three stacked minor thirds. A♭ is a black key; C♭, E♭♭ and G♭♭ are white. - Canonical page: https://piano.org/chords/diminished-7th/a-flat/ - Entity: chord:diminished-7th:a-flat - Notes: A♭ C♭ E♭♭ G♭♭ - Formula: 1 ♭3 ♭5 ♭♭7 - Intervals from root: P1, m3, TT, M6 - Interval stack (semitones): 3 3 3 - Also written: A♭dim7, Abdim7, A♭ diminished 7th - Parameters: A440, 12-TET, 165 mm octave, spans centre to centre ## Construction | Degree | Note | Interval from root | Semitones | | --- | --- | --- | --- | | 1 | A♭ | Perfect unison | 0 | | ♭3 | C♭ | Minor third | 3 | | ♭5 | E♭♭ | Tritone | 6 | | ♭♭7 | G♭♭ | Major sixth | 9 | ## Fingering Rest your right hand over the notes with finger 2 on A♭, finger 3 on C♭, finger 4 on E♭♭, finger 5 on G♭♭. The left hand mirrors it. Right hand 2-3-4-5, left hand 5-4-3-2. Source: piano.org fingering method v1. ## Inversions | Position | Bass | Notes in order | Figured bass | Span | | --- | --- | --- | --- | --- | | Root position | A♭ | A♭3 C♭3 E♭♭4 G♭♭4 | 7 | 9 st, 124 mm | | First inversion (A♭dim7/C♭) | C♭ | C♭3 E♭♭4 G♭♭4 A♭4 | 6/5 | 9 st, 124 mm | | Second inversion (A♭dim7/E♭♭) | E♭♭ | E♭♭4 G♭♭4 A♭4 C♭4 | 4/3 | 9 st, 124 mm | | Third inversion (A♭dim7/G♭♭) | G♭♭ | G♭♭4 A♭4 C♭4 E♭♭5 | 4/2 | 9 st, 124 mm | ## Voicings (10) | Voicing | Notes | Span | Relation | Omits or adds | | --- | --- | --- | --- | --- | | Close, root position | A♭3 C♭3 E♭♭4 G♭♭4 | 9 st, 124 mm | identical | none | | Close, first inversion | C♭3 E♭♭4 G♭♭4 A♭4 | 9 st, 124 mm | identical | none | | Close, second inversion | E♭♭4 G♭♭4 A♭4 C♭4 | 9 st, 124 mm | identical | none | | Close, third inversion | G♭♭4 A♭4 C♭4 E♭♭5 | 9 st, 124 mm | identical | none | | Drop 2 | E♭♭3 A♭3 C♭3 G♭♭4 | 15 st, 206 mm | identical | none | | Drop 3 | C♭2 A♭3 E♭♭4 G♭♭4 | 18 st, 248 mm | identical | none | | Drop 2 and 4 | A♭2 E♭♭3 C♭3 G♭♭4 | 21 st, 289 mm | identical | none | | Shell, root ♭♭7 ♭3 | A♭2 G♭♭3 C♭3 | 15 st, 206 mm | subset | omits E♭♭ | | Guide tones, ♭3 and ♭♭7 | C♭3 G♭♭4 | 6 st, 83 mm | subset | omits A♭ and E♭♭ | | Rootless close | C♭3 E♭♭4 G♭♭4 | 6 st, 83 mm | subset | omits A♭ | ## One-edit neighbors | Becomes | Edit | Changes | Common tones | | --- | --- | --- | --- | | A♭dim | 1 ♭3 ♭5 | drops G♭♭ | 3 | | A♭m7♭5 | 1 ♭3 ♭5 ♭7 | G♭♭ becomes G♭ | 3 | | A♭m6 | 1 ♭3 5 6 | E♭♭ becomes E♭ | 3 | | A♭m | 1 ♭3 5 | E♭♭, G♭♭ becomes E♭ | 2 | | A♭m7 | 1 ♭3 5 ♭7 | E♭♭, G♭♭ becomes E♭, G♭ | 2 | | A♭mMaj7 | 1 ♭3 5 7 | E♭♭, G♭♭ becomes E♭, G | 2 | | A♭6 | 1 3 5 6 | C♭, E♭♭ becomes C, E♭ | 2 | ## Set theory - Absolute pitch classes: {8, 11, 2, 5} - Relative pitch classes: [0, 3, 6, 9] - Normal order: [2, 5, 8, 11] - Prime form: (0369) - Forte number: 4-28 - Interval vector: <004002> ## Frequencies (close root position) | Note | MIDI | Frequency | | --- | --- | --- | | A♭3 | 56 | 207.65 Hz | | C♭3 | 59 | 246.94 Hz | | E♭♭4 | 62 | 293.66 Hz | | G♭♭4 | 65 | 349.23 Hz | ## Questions and answers ### What notes are in A♭dim7? A♭dim7 contains A♭, C♭, E♭♭ and G♭♭. The formula is 1, ♭3, ♭5, ♭♭7. ### How do you play A♭dim7 on piano? Play A♭, C♭, E♭♭ and G♭♭ together. Right hand fingers 2, 3, 4, 5; left hand 5, 4, 3, 2. A♭ is a black key; C♭, E♭♭ and G♭♭ are white. ### What are the inversions of A♭dim7? 4 positions: root position A♭ C♭ E♭♭ G♭♭, A♭dim7/C♭, A♭dim7/E♭♭, A♭dim7/G♭♭. ### What is the difference between A♭dim7 and A♭dim? Drops G♭♭. 3 of the notes are shared. ### What is an easy A♭dim7 for small hands? The guide tones, ♭3 and ♭♭7 voicing, C♭3 G♭♭4, spans 6 semitones or about 83 mm. ### What are the frequencies of A♭dim7? From A♭3 at A440 in 12-TET: 207.65, 246.94, 293.66, 349.23 Hz. ### What is the set class of A♭dim7? Prime form (0369), Forte 4-28, interval vector <004002>. ### How do I transpose A♭dim7 to another key? Keep the 1, ♭3, ♭5, ♭♭7 formula on the new root. C♯dim7 is C♯, E, G, B♭; Ddim7 is D, F, A♭, C♭. ### Is G♯dim7 the same as A♭dim7? Enharmonically yes: the same piano keys and the same sound, spelled differently. ## Provenance Every derived value above is computed by the piano.org theory kernel from the root, the quality and the stated parameters. Nothing is hand-entered per chord. Machine record: https://piano.org/api/knowledge/v1/entities/chord:diminished-7th:a-flat Last reviewed: 2026-08-12