A# Diminished
Introduction
Enharmonic equivalent: A♯ is enharmonically equivalent to B♭. See Bb Diminished.
Notes
A# Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | A#4 – C#5 – E5 |
| 1st Inversion | C#5 – E5 – A#5 |
| 2nd Inversion | E5 – A#5 – C#6 |
Key Signature
The key of A# Diminished has Key signature data not available.
Theory: Intervals
The A# Diminished is built by stacking intervals from the root note. The formula R-m3-d5 describes the scale degrees used. The intervals P1-m3-d5 show the distance between each note in the chord.
A# Diminished — Frequently Asked Questions
What notes are in the A# Diminished chord?
The A# Diminished chord contains: A# (root), C# (minor third), and E (diminished fifth). Both intervals are compressed: the minor third is 3 semitones above the root, and the diminished fifth is 6 semitones — a tritone.
How does A# Diminished differ from A# Minor?
A# Minor has a perfect fifth. A# Diminished lowers the fifth by one semitone to E (diminished fifth). That extra compression creates intense harmonic tension — the tritone between root and diminished fifth is the most dissonant interval in Western music.
What is the symbol for the A# Diminished?
A# Diminished is written as A#dim or A#°. The ° or "dim" symbol means both the third and fifth are minor/diminished. Do not confuse with A#dim7 or A#ø (half-diminished), which include additional notes.
What are the inversions of A# Diminished?
First inversion (A# Diminished/C#): C#–E–A#. Second inversion (A# Diminished/E): E–A#–C#. Diminished triads are used in classical music as the vii° chord — the chord one semitone below the tonic, with strong resolution pull.
How is A# Diminished used in music?
A# Diminished most commonly functions as the vii° chord in a major key, creating strong resolution back to the tonic. It also works as a chromatic passing chord between two nearby chords, and in classical music as a brief point of dissonance. Jazz uses the full four-note dim7 more often than the triad.
What songs use diminished chords?
Michelle (Beatles) uses a diminished chord as a chromatic passing chord. Many classical pieces use vii°–I cadences. Jazz standards use dim7 chords as chromatic passing and approach chords. Diminished harmony also appears in flamenco and film music for dramatic tension.
Practice Tips
- Compare A# Minor and A# Diminished: only the fifth changes (E vs perfect fifth). Play both back to back — the extra compression is striking.
- The tritone between A# and E creates maximum tension — practice just this two-note interval to hear its characteristic sound.
- A# Diminished most naturally resolves up by half step: play A#dim then a chord whose root is A# raised by one semitone.
- Practice all inversions: A#–C#–E, C#–E–A#, E–A#–C#.
- Use A# Diminished as a vii° chord: it is one semitone below A## Major — try A#dim → A## Major to feel this powerful classical resolution.
- In a major key, find where A# Diminished fits naturally as a passing chord between two diatonic chords a step apart.