Suspended Chords

Major dominant ninth with suspended fourth
Major dominant ninth with suspended fourth.

Hyacinth / Wikimedia Commons / CC BY-SA 3.0

A suspended chord—abbreviated sus on music sheets and tabs—is a musical chord which is a variation on the major or minor triads. Suspended fourths are abbreviated [key] "sus" [type of suspension], so a suspended second in G is abbreviated Gsus2, and a suspended fourth in C major is Csus4. In contrast to major and minor chords ("resolved" chords), suspended chords are "unresolved" chords, which types also include diminished and augmented. Suspended chords are one way musicians communicate and listeners hear sensory dissonance.

Building a Suspended Chord

To build a common triad in a major or minor scale, the musician uses the three main notes in the scale: 1 (the root), 3, and 5. In C major, those three notes are C+E+G.

To make a suspended chord, the musician replaces the third note with the second or fourth. So, in a C major suspended chord, if you replace the E with a D, you get a suspended second chord (1+2+5 or C+D+G); if you replace the E with an F you get a suspended fourth chord (1+4+5 or CFG or 1+4+5).

Sus2 and Sus4 Chords

  • sus4: A sus4 chord replaces the 1+3+5 pattern with 1+4+5, meaning the third note is replaced by the fourth. If, for example, the tab says you need to play a Dsus4 chord, instead of playing D+F#+A (=1+3+5) you raise the middle note or the third note by a half step. So a Dsus4 chord is D+G+A (=1+4+5). Here are some commonly used sus4 chords for guitar, and piano.
  • sus2: The sus2 chord follows the pattern 1 (root) + 2 + 5, so if in a sus4 chord you play the root, fourth and fifth notes, for a sus2 chord you play the root, second and fifth notes. In other words, from a sus4 chord, you lower the middle note three half steps. For example, a Dsus2 chord is D+E+A. Here are some commonly used sus2 chords for guitar and piano.

A Bit of History

Suspended chords were invented in the 16th century when Renaissance musicians used it as the primary way to get dissonance into counterpoint music. Basically, plainchant of the 14th century employed 3-toned chords but by the Renaissance, musicians became more interested in polyphonic chords and less interested in the "perfect" consonant intervals.

Suspended chords are particularly important in jazz music, and they were especially important in the late 1960s, when they were used to build independent sonorities in modal jazz styles by musicians such as Bill Evans and McCoy Tyner. The suspended fourth is by far the most commonly used.