Add #11

Notes and formula

The formula is 1 – 3 – 5 – ♯11, or 0 – 4 – 7 – 18 in semitones. The eleventh is raised, which places it a whole tone above the third rather than a semitone.

That single semitone of difference changes everything about how the chord can be voiced. Where Cadd11 demands wide spacing to be usable, this chord is clear in any arrangement, including a close cluster.

How to play it

On guitar the shape is x–3–2–0–x–2, sounding C–E–G–F♯. The raised eleventh sits on the top string and rings against the open third string's fifth.

On piano it works in close position, and it is one of the few added-note chords that does. C–E–F♯–G is clear; the same voicing with F natural is not.

Where it comes from

Lydian. The raised fourth is that mode's defining degree, and putting it into a triad without a seventh states the mode in the smallest possible way.

It is also what a major triad becomes when a bass line moves below it: hold a C triad over an F♯ or a D and the resulting sonority contains these notes, which is how the chord often reaches an arrangement.

How it sounds and where you hear it

Weightless. The triad keeps the chord anchored while the raised fourth removes any sense of a key centre, and the combination reads as openness rather than tension.

Film scoring uses it for scale and distance. Jazz and fusion use it wherever a major chord is not the tonic. In pop it appears where a guitar part is built from open strings and the F♯ is simply what rang.

Against the neighbours

Cadd11 has the natural fourth and is tense. Cmaj7♯11 adds a major seventh and is the full jazz version. Cadd♯11 is the version with neither the tension nor the seventh — the plainest way to state Lydian.

Because it has no seventh, it does not commit a passage to a jazz idiom, which is exactly why it is useful in film and pop.

Scales that contain it

Lydian fits exactly. Nothing else does without alteration: Ionian and Mixolydian both contain the natural fourth the chord raises.

For a melody this is a licence rather than a restriction — the raised fourth becomes a note to land on rather than to pass through, which is what makes Lydian writing sound the way it does.

Frequently asked questions