A♯ Half-Whole Diminished at a glance
The half-whole diminished is the standard scale over a dominant 7♭9 chord in jazz. Its symmetry means a phrase transposed by minor third still fits the chord, perfect for fast harmonic motion. Built on the root A♯, the scale takes on the specific colour and pitch range of that key - making it especially useful in genres and registers where A♯ is a comfortable tonal centre.
| Notes | A♯ B C♯ C𝄪 D𝄪 E♯ F𝄪 G♯ |
|---|---|
| Formula | 1P · 2m · 3m · 3M · 4A · 5P · 6M · 7m |
| Step pattern | H W H W H W H W |
A♯ Half-Whole Diminished on the piano
Improvisation drone · A♯
Loop the root note as a pad to practice improvising over this scale.
On the piano A♯ Half-Whole Diminished uses three black keys (A♯, C♯ and G♯) and five white. C𝄪, D𝄪, E♯ and F𝄪 are the white keys you'd normally call D, E, F and G.
A♯ · B · C♯ · C𝄪 · D𝄪 · E♯ · F𝄪 · G♯
Try A♯ Half-Whole Diminished on the virtual piano
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A♯ Half-Whole Diminished on the guitar
A♯ Half-Whole Diminished - fr 0–12
A♯ Half-Whole Diminished on the staff
Notes of the A♯ Half-Whole Diminished scale
| Degree | Note | Interval | Semitones | Hear |
|---|---|---|---|---|
| 1 | A♯ | unison1P | 0 | |
| 2 | B | minor 2nd2m | 1 | |
| 3 | C♯ | minor 3rd3m | 3 | |
| 4 | C𝄪 | major 3rd3M | 4 | |
| 5 | D𝄪 | augmented 4th4A | 6 | |
| 6 | E♯ | perfect 5th5P | 7 | |
| 7 | F𝄪 | major 6th6M | 9 | |
| 8 | G♯ | minor 7th7m | 10 |
What makes A♯ Half-Whole Diminished different
The half-whole diminished scale has eight notes that alternate a half step and a whole step, so its pattern repeats every minor third. That symmetry means there are only three different ones: the scale on C has the same notes as those on E♭, G♭ and A. It holds the 1, 3, 5 and ♭7 of a dominant chord plus the ♭9, ♯9 and ♯11. Its natural fifth and natural 13th are what separate it from the Altered scale over the same chord.
How to use the A♯ Half-Whole Diminished scale
Because A♯ Half-Whole Diminished has fewer or more than seven notes, it doesn't produce a standard set of seven diatonic triads. Instead, build chords by stacking thirds within the scale or use it as a melodic colour over chords drawn from a related diatonic key.
The half-whole diminished is the standard scale over a dominant 7♭9 chord in jazz. Its symmetry means a phrase transposed by minor third still fits the chord, perfect for fast harmonic motion.
Practice tips
Practise the scale starting from each chord tone of the underlying dominant 7♭9 (1, ♭3, ♭5, ♭♭7) — they're all four equivalent because of the symmetry, and that insight is what makes diminished playing fast and fluid.
Formula & step pattern
The A♯ Half-Whole Diminished scale follows an eight-note symmetric scale alternating half-step then whole-step (1, ♭2, ♭3, 3, ♯4, 5, 6, ♭7). Step pattern: H - W - H - W - H - W - H - W. Intervals from the root: 1P · 2m · 3m · 3M · 4A · 5P · 6M · 7m. Memorising the formula lets you transpose the scale to any other root note quickly.
Where you will hear A♯ Half-Whole Diminished
Start with the music described above: listen for A♯ Half-Whole Diminished in it and transcribe a few short phrases by ear. It's the quickest way to learn how the scale sounds.
Questions people ask
What notes are in the A♯ Half-Whole Diminished scale?
The A♯ Half-Whole Diminished scale contains A♯, B, C♯, C𝄪, D𝄪, E♯, F𝄪 and G♯.
What is the formula for the A♯ Half-Whole Diminished scale?
A♯ Half-Whole Diminished follows an eight-note symmetric scale alternating half-step then whole-step (1, ♭2, ♭3, 3, ♯4, 5, 6, ♭7).
Is A♯ Half-Whole Diminished a major or minor scale?
A♯ Half-Whole Diminished is a half-whole diminished scale. Octatonic scale alternating half then whole steps — symmetric, dissonant, the standard choice over a dominant 7♭9 chord in jazz.
What chords belong to the A♯ Half-Whole Diminished scale?
A♯ Half-Whole Diminished doesn't produce a standard seven-chord diatonic set. Use chords from a related diatonic scale instead.
Which genres use A♯ Half-Whole Diminished?
The half-whole diminished is the standard scale over a dominant 7♭9 chord in jazz. Its symmetry means a phrase transposed by minor third still fits the chord, perfect for fast harmonic motion.
How do you play the A♯ Half-Whole Diminished scale on the piano?
On the piano A♯ Half-Whole Diminished uses three black keys (A♯, C♯ and G♯) and five white. C𝄪, D𝄪, E♯ and F𝄪 are the white keys you'd normally call D, E, F and G.
How do I practise the A♯ Half-Whole Diminished scale?
Practise the scale starting from each chord tone of the underlying dominant 7♭9 (1, ♭3, ♭5, ♭♭7) — they're all four equivalent because of the symmetry, and that insight is what makes diminished playing fast and fluid.