Aadd9 chord on guitar
Aadd9 (A add 9) is a add9 chord built on A. It has 4 notes, A, C♯, E and B, and its formula is 1 3 5 9.
Notes and intervals of Aadd9
From the root upwards, Aadd9 contains root (A), major 3rd (C♯), perfect 5th (E) and major 9th (B). Those intervals give the chord its colour: the formula 1 3 5 9 works the same way in every key, so once you know it for A you can build the chord on any note.
| Degree | Interval | Note |
|---|---|---|
| 1 | root | A |
| 3 | major 3rd | C♯ |
| 5 | perfect 5th | E |
| 9 | major 9th | B |
How to play Aadd9 on guitar
The first shape above reads x 0 2 4 2 0 from the low E string to the high E string (x means you do not play that string, 0 is an open string). The lowest note you play is A. The other diagrams show the same chord higher up the neck: pick the one closest to the chords before and after it in your song.
Let the open strings ring: strum slowly once and check that every note sounds clean before you speed up.
Which keys use Aadd9?
Aadd9 is not built from the notes of a single major key, so it usually appears as a colour chord: a borrowed chord, a passing chord or a suspension that resolves to the next chord.
Scales to play over Aadd9
To improvise over Aadd9, start with A major scale. All of these scales contain every note of the chord: A major scale, A major pentatonic scale, A Lydian mode and A Mixolydian mode. Aim for the chord notes on strong beats and use the other notes to move between them.
About add9 chords
A major triad with the 9th added: 1 3 5 9. Unlike a 9 chord there is no seventh, so the add9 chord stays bright and simple, with a sparkle on top. The 9 (the second, an octave higher) rubs gently against the third and the root, which gives that shimmering acoustic pop sound. For example Cadd9: C E G D.
Use it anywhere a major chord fits, mostly on I and IV, to enrich a plain progression without changing its function (for example Cadd9 G D Em in G major). Acoustic pop, worship, country and indie use it constantly, often keeping one note ringing on the top strings through a whole progression as a drone.
The famous open Cadd9 (x32033) keeps the 3rd and 4th fingers on the top strings, so it switches easily with G (320033) and Em7 (022033). The movable version is a stretch with the root on the 5th string and the 9 on the 3rd string, four frets above the root (for example Cadd9 x3575x). Let the open strings ring when you can.
add9 versus 9: a 9 chord also contains the ♭7 and has a dominant sound, add9 does not. add9 versus sus2: sus2 drops the third, add9 keeps it. And add9 versus add2: same note names, but add2 implies the second sits close to the root, add9 an octave higher. Many charts use them loosely, so trust your ears.
Frequently asked questions
What notes are in the Aadd9 chord?
Aadd9 (A add 9) contains A, C♯, E and B. In intervals: root (A), major 3rd (C♯), perfect 5th (E) and major 9th (B).
How do you play Aadd9 on guitar?
The easiest shape is x 0 2 4 2 0, from the low E string to the high E string. This page shows 3 positions with finger numbers.
What scale goes with Aadd9?
A major scale fits Aadd9 best. Other scales that contain all its notes: A major pentatonic scale, A Lydian mode and A Mixolydian mode.
What key is Aadd9 in?
Aadd9 does not belong to a single major key. It is used as a colour chord that borrows notes from outside the key.
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