Suspended Chord

A suspended chord (sus chord) is a chord in which the (major or minor) third is omitted, replaced usually with either a perfect fourth ( play) or a major second ( play), although the fourth is far more common. The lack of a minor or a major third in the chord creates an open sound, while the tension between the fourth and fifth or second and root creates dissonance.

The term is borrowed from the contrapuntal technique of suspension, where a note from a previous chord is carried over to the next chord, and then resolved down to the third or tonic, suspending a note from the previous chord. However, in modern usage, the term concerns only the notes played at a given time; in a suspended chord the added tone does not necessarily resolve, and is not necessarily "prepared" (i.e., held over) from the prior chord. As such, in C-F-G, F would resolve to E, but in rock and popular music, "the term is used to indicate only the harmonic structure, with no implications about what comes before or after," though preparation of the fourth occurs about half the time and traditional resolution of the fourth occurs usually. In modern jazz, a third can be added to the chord voicing, as long as it is above the fourth.

Each suspended chord has two inversions. Suspended second chords are inversions of suspended fourth chords, and vice versa. For example, Gsus2 (G-A-D) is the first inversion of Dsus4 (D-G-A) which is the second inversion of Gsus2 (G-A-D). The sus2 and sus4 chords both have an inversion that creates a quartal chord with two stacked perfect fourths.

Suspended fourth and second chords can be represented, in integer notation, as {0, 5, 7} and {0, 2, 7} respectively. The second inversion (quartal chord) is {0, 5, 10}.

Sevenths on suspended chords are "virtually always minor sevenths", while the 9sus chord is similar to an eleventh chord and may be notated as such. For example C9sus (C, F, G, B♭, D) may be notated C11 (C, —, G, B♭, D, F).