A Augmented Triad
Chord Tones: A Augmented Triad
Symbol: aug, + — Formula: 1-3-♯5
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | A | 440.000 Hz |
| 3 | C# | 277.183 Hz |
| ♯5 | F | 349.228 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Aaug |
| All Common Symbols | aug, + |
| Interval Formula | 1-3-♯5 |
| Harmonic Category | unstable |
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# – F | A | A Augmented Triad |
| First Inversion | C# – F – A | C# | A Augmented Triad/C# |
| Second Inversion | F – A – C# | F | A Augmented Triad/F |
Harmonic Function
The A augmented 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 augmented triad consists of two stacked major thirds, creating a symmetrical, ambiguous chord. Its raised fifth gives it a tense, unresolved quality that pulls toward resolution.
Common Progressions
The A Augmented Triad frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
I+-IVV+-I
Songs Featuring the Augmented Triad
Well-known songs where the A Augmented Triad — or this chord type — plays a prominent role:
- Oh! You Pretty Things – David Bowie
- All Blues – Miles Davis
- Michelle – The Beatles
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# | 277.183 Hz | 278.437 Hz | 279.067 Hz |
| F | 349.228 Hz | 347.654 Hz | 348.834 Hz |
Scales Containing the A Augmented Triad
These scales include the A Augmented Triad as a diatonic or characteristic chord: