E Suspended 4th
sus4
0 - 5 - 7Root + perfect 4th + perfect 5th
About E Suspended 4th
Esus4 replaces the G♯ of an E major chord with an A — E, A, B — and on guitar that means moving one finger to the second fret of the G string. The chord keeps all six strings ringing, which makes it the loudest suspension available and a favourite of anyone writing with open tunings in mind.
The notes
E, A, B. No third, so no mode; the fourth leans toward the third it replaced, and releasing the finger resolves it.
Because E is the guitar’s home key, this chord has more open strings than any other suspension — three of the six, all belonging to the chord, which is why it sustains so long.
How it is used
Alternating with E on the beat. The figure is identical in function to Asus4 or Dsus4, and louder than either, which suits it to rock rather than to fingerstyle.
Held longer it works as a modal chord: with no third, an E–Esus4 vamp sits comfortably under both a major and a minor melody, and songwriters use that ambiguity deliberately.
Where it shows up
In the key of E before the tonic, and in the key of B as a suspended IV. It also opens a great many rock songs, where the resolution to plain E is the first thing the listener hears.
In drop-D and open tunings the chord often arrives by accident — an open string that happens to be the fourth — and stays because it works.
It is also the suspension most often left unresolved. Because the chord rings so fully, ending a phrase on Esus4 sounds deliberate rather than unfinished — a licence the quieter suspensions do not have.