Altered and extended chords (sus, add, aug, dim, ø7)

Beyond major and minor

The major and minor triad are only the beginning. By replacing or adding tones we get colour chords that add tension, ambiguity or brightness. Here is an overview of the most important families, which you will also find on chord.si.

Suspended chords (sus)

Sus chords replace the third - the tone that decides between major and minor - with another tone. sus2 uses the 2nd degree (Csus2 = C-D-G), sus4 the 4th degree (Csus4 = C-F-G). Without a third they sound open and 'unresolved' - they like to resolve back to a plain chord.

Added-note chords (add)

add chords add a tone to a plain triad without stacking a seventh in between. Cadd9 = C-E-G-D adds the ninth - a bright, modern pop sound popular with guitarists.

Augmented and diminished

• Augmented (aug, +) - raised fifth: Caug = C-E-G♯. Tense, floating, dreamlike; often links two chords.
• Diminished (dim, °) - minor triad with a lowered fifth: Cdim = C-E♭-G♭. Unstable, tense.
• Diminished seventh (dim7) - stacked minor thirds: symmetrical, can lead to almost any key.
• Half-diminished (ø7, m7♭5) - Cm7♭5 = C-E♭-G♭-B♭. The heart of the minor ii-V-i progression.

You meet these chords most often in jazz, bossa nova and film music. Once you master them, the full colour palette of harmony is at your disposal.