Diminished and augmented triads
Build and recognise diminished and augmented triads.
Stacking two minor 3rds or two major 3rds gives the two remaining triads. Both sound tense.
Diminished
The diminished triad is two minor 3rds: 1 ♭3 ♭5. C° = C E♭ G♭. It sounds tense and unstable, because the root and the ♭5 form a tritone. In a major key it appears naturally on the 7th degree (B° in C major).
Augmented
The augmented triad is two major 3rds: 1 3 ♯5. C+ = C E G♯. It sounds tense, “suspended in the air”. It does not occur in the major or natural minor scale; it is usually a passing chord.
The augmented triad is symmetrical: C+, E+ and G♯+ (= A♭+) contain the same three pitches, just named differently. This makes it useful for moving between keys.
All four types
| Triad | Intervals | Degrees | Notes from C |
|---|---|---|---|
| Major | M3 + m3 | 1 3 5 | C E G |
| Minor | m3 + M3 | 1 ♭3 5 | C E♭ G |
| Diminished | m3 + m3 | 1 ♭3 ♭5 | C E♭ G♭ |
| Augmented | M3 + M3 | 1 3 ♯5 | C E G♯ |
Spelling matters here too: A+ is A C♯ E♯, not F; B♭+ is B♭ D F♯, not G♭.
Play C, Cm, C° and C+ arpeggios one after the other from the same root. Only the 3rd and 5th move: say which way each time.
New terms
Tools
- Chords for Bass: Every common chord type on all 12 roots, as a 5-fret box for 4- and 5-string bass, with spelled notes and formulas.