Chords
A chord is three or more different notes played together.
Triads
A triad has three notes:
- Root
- Third
- Fifth
The third decides if the chord is major or minor.
Other basic triads
- Diminished: minor third + diminished fifth
- Augmented: major third + augmented fifth
Seventh chords
A seventh chord adds a fourth note above the triad:
- Major seventh: major triad + major seventh
- Minor seventh: minor triad + minor seventh
- Dominant seventh: major triad + minor seventh
Extended chords
- Sixth chord: triad + sixth
- Ninth chord: triad + seventh + ninth
- Eleventh chord: triad + seventh + eleventh
Altered, suspended, and power chords
- Altered chords change one or more notes.
- Suspended chords replace the third with a second (sus2) or fourth (sus4).
- Power chords use only the root and fifth.
Inversions
An inversion changes which note is at the bottom:
- First inversion: third is lowest
- Second inversion: fifth is lowest
- Seventh chords and larger chords have further inversions
Chord progressions
Chords often follow patterns within a key. The tonic (I) is the home chord in major keys. The V chord naturally leads back to I.
Chord leading
Some chords move smoothly to others. A common example is V → I, which gives a strong sense of resolution.
Sources
- The Complete Idiot's Guide To Music Theory by Michael Miller
- Music Theory For Dummies by Michael Pilhofer and Holly Day
- Harmony and Theory: A Comprehensive Source for All Musicians (Essential Concepts) by Keith Wyatt and Carl Schroeder