The A flat diminished chord contains A♭, C♭ and E𝄫 (E double flat). Written A♭dim, it is a three-note triad with formula 1–♭3–♭5. On the piano, C♭ uses the B key and E𝄫 uses D.
Build the A flat diminished chord by stacking two minor thirds: A♭ to C♭, then C♭ to E𝄫. Each spans three semitones. Keep the letter names A–C–E to show the root, third and fifth, even when the keys have simpler alternative names.
Preserve the written spelling C♭, E𝄫 even when it shares a piano key with a simpler enharmonic name.
Choose a position to keep the written notes, sounding keys, bass note, playback and print reference synchronized.
Select A♭, B and D in the exercise. The B and D keys represent the written notes C♭ and E𝄫. The exercise checks three pitch classes, so it accepts those sounding keys while the reference preserves its theoretical spelling.
A♭dim uses 1–♭3–♭5: A♭–C♭–E𝄫.
Compared with A♭ minor, lower the fifth by one semitone.
The chord tones stay the same while the lowest chord tone changes.
| Position | Symbol | Notes, low to high | Bass |
|---|---|---|---|
| Root position, current selection | A♭dim | A♭3–C♭4–E𝄫4 | A♭3 |
| First inversion | A♭dim/C♭ | C♭4–E𝄫4–A♭4 | C♭4 |
| Second inversion | A♭dim/E𝄫 | E𝄫4–A♭4–C♭5 | E𝄫4 |
The A flat diminished chord diagrams show note positions without prescribing fingers. C♭4 sounds on B3, crossing the written C octave boundary; E𝄫4 sounds on D4. Read both the written note and its sounding key before comparing inversions.
Use the written notes, keyboard positions and playback without treating the diagram as a required hand shape.
Read left- and right-hand finger numbersOpen Music Theory
Supports: diminished triad formula and written tone spelling
Scope: Supports the chord formula and spelling only; keyboard layouts are PianoGrid examples, and no fingering is assigned.
A♭, C♭ and E𝄫. C♭ lowers C by one semitone; E𝄫 lowers E by two. They sound on the B and D keys of the piano.
No. A♭ minor uses E♭ as its fifth. The A flat diminished chord lowers that fifth another semitone to E𝄫; both chords use C♭ as their third.
No. This reference contains three notes. A fully diminished seventh chord adds a fourth chord tone; the dim7 symbol names that different four-note chord.
The first inversion puts C♭ lowest; the second puts E𝄫 lowest. All three chord tones remain present. Select a position above to compare the note order, diagram and sound.
Select the three pitch classes that make A♭dim, then check your answer.
This one-octave exercise checks pitch classes. Order and octave do not affect the result; fingering and live performance are not assessed.
One octave, C through B. Select a key again to remove it.
Chord tones: A♭–C♭–E𝄫 · Formula: 1, ♭3, ♭5
Dots mark the notes to play. C4 is middle C. Numbers identify octaves, not fingers.