Stackapella Open the app

Four notes · 1 3 5 9 · pure 8:9:10:12

The add9 chord

An add9 chord is a major chord with the ninth added: the note a whole step above the root, usually placed an octave up. It sounds bright and open, with a gentle shimmer and no seventh to pull it anywhere.

How it's built

Add the ninth to a major chord: C, E, G and D. The ninth is the second note of the scale counted past the octave, which is why it's called 9. "Add" means only that note joins the chord: there's no seventh, unlike C9, which is C, E, G, B♭ and D. And the third stays, unlike a sus2.

Singing it in tune

Tuned pure, it's 8:9:10:12 in close position. The ninth, 9:8, sits 3.9 cents (a cent is a hundredth of a semitone) above the piano's, the third 13.7 below, the fifth 2.0 above. The ninth hardly moves because it's a pure fifth above the chord's fifth.

Voiced with the ninth on top, an octave up, the chord is 4:5:6:9, all harmonics of one low note. In close position the ninth sits a whole step below the third, and pure tuning makes that whole step a small 10:9, 17.6 cents narrower than the piano's.

Where you hear it

In pop, rock, folk and worship songs, often on the home chord or the fourth chord of the key. In choirs and a cappella arrangements, the ninth often sits in an upper voice to brighten a plain major chord, sometimes on the final chord. The minor version, with a minor third, is written m(add9).

More chord types

Free tools by Stackapella

All of these are free, and so is every course.

Stackapella teaches you to sing harmony one part at a time, right in your browser.

Stackapella recording the alto part of Amazing Grace: each note is a bar with its name, and the one being sung says A little low, go up. Stackapella recording the alto part of Amazing Grace: each note is a bar with its name, and the one being sung says A little low, go up. Stackapella recording the alto part of Amazing Grace: each note is a bar with its name, and the one being sung says A little low, go up. Stackapella recording the alto part of Amazing Grace: each note is a bar with its name, and the one being sung says A little low, go up.
  • A guide sings your partHear your line over the others, slow it down, then take your turn.
  • Your notes light upEach note shows where you landed, and a hint when to go up or down.
  • Record every part yourselfStack your takes in time until you're the whole choir.
Start the beginner course Open the app How Stackapella works

Questions

What is the difference between add9 and sus2?

The third. An add9 keeps it, so it's still a major chord with a ninth on top: C, E, G and D. A sus2 drops the third for that same D: C, D and G, neither major nor minor.

What is the difference between add9 and a 9 chord?

A 9 chord has a seventh as well and an add9 doesn't. C9 is C, E, G, B♭ and D, a dominant 7th with a ninth; C add9 is C, E, G and D.

Is add9 the same as add2?

Nearly: they have the same notes. Add2 usually means the second sits close, next to the root or the third, and add9 that it sits above the octave, though many chord charts use the two names for the same thing.

More free tools

No account, no ads. Each one keeps working offline once you've opened it.

See all 17 tools
Ready to tell them apart by ear? Try chord ear trainingChord ear training · Major, minor or seventh: which?