Sus4 Chord
The third is replaced by the fourth: C, F and G. That fourth sits one half step above the note it pushed out, and your ear hears it as something that has not landed yet.
- 3 notes
- 1 4 5
- leaning
which styles use it
- Gospel
- Rock & folk
- Pop
- Worship
Which notes are in a sus4 chord?
The root, the fourth and the fifth. In C: C, F and G. The E that would make it major or minor is gone, so the chord refuses to say which of the two it is.
- C, the root
- F, the fourth, standing where the third belongs
- G, the fifth
Why does it sound unfinished?
Because of where the name comes from. A suspension in classical music is three separate events. First the preparation: the note is already sounding, comfortably, as part of the previous chord. Then the suspension: the harmony underneath changes but that note stays put, so it becomes a dissonance, usually on a strong beat. Then the resolution: it falls one step to the note it was covering.
That last step is the 4 to 3 suspension, and it is exactly what you hear when Csus4 goes to C. The F drops to E and the chord finally says what it is.
So why does it stay unresolved in pop songs?
Because players stopped following the rule. In pop, rock and jazz the suspension is often left hanging with no preparation in front of it and no resolution behind it, which turns it from an event in time into a colour you can hold.
An Fsus4 that lasts four bars does not sound unfinished, it sounds open. Both uses are correct, and it is worth knowing which of the two you are playing.
sus4, sus2 or the plain triad?
Same root, same fifth, and the argument is only ever about the third.
- C (C E G) - The third is there. The chord has a mood.
- Csus4 (C F G) - The third is replaced from above. Leans downward and wants to resolve.
- Csus2 (C D G) - The third is replaced from below. Much less tense, more open than unfinished.
- Cadd9 (C E G D) - Nothing is replaced. The third stays and the D is added an octave higher, as a sparkle on a normal chord.
Common mistakes
- Writing sus without a number
In practice a bare sus means sus4, but write sus4 or sus2 and nobody has to guess.
- Resolving it every single time
The resolution is the classical use. If the song wants openness rather than tension, let it stand.