A Diminished Triad
Chord Tones: A Diminished Triad
Symbol: dim, ° — Formula: 1-♭3-♭5
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | A | 440.000 Hz |
| ♭3 | C | 261.626 Hz |
| ♭5 | D# | 311.127 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Adim |
| All Common Symbols | dim, ° |
| Interval Formula | 1-♭3-♭5 |
| Harmonic Category | dissonant |
Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.
Inversions
| Inversion | Notes (low to high) | Bass Note | Slash Notation |
|---|---|---|---|
| Root Position | A – C – D# | A | A Diminished Triad |
| First Inversion | C – D# – A | C | A Diminished Triad/C |
| Second Inversion | D# – A – C | D# | A Diminished Triad/D# |
Harmonic Function
The A diminished chord commonly functions as the submediant (vi) in C major or dominant (V) in D major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.
The diminished triad features a flat third and flat fifth, creating a tense, unstable sound. It occurs naturally on the seventh degree of the major scale and resolves strongly to the tonic.
Common Progressions
The A Diminished Triad frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
vii°-Iii°-V
Songs Featuring the Diminished Triad
Well-known songs where the A Diminished Triad — or this chord type — plays a prominent role:
- Whole Lotta Love – Led Zeppelin (bridge)
- Killing Me Softly – Roberta Flack
- Black Magic Woman – Santana
Tuning Frequencies Across Temperaments
Frequencies shown at A=440 Hz. View full temperament data for any note.
| Note | Equal Temp. | Pythagorean | Just Intonation |
|---|---|---|---|
| A | 440.000 Hz | 440.000 Hz | 436.043 Hz |
| C | 261.626 Hz | 260.740 Hz | 261.626 Hz |
| D# | 311.127 Hz | 309.026 Hz | 313.951 Hz |
Scales Containing the A Diminished Triad
These scales include the A Diminished Triad as a diatonic or characteristic chord: