A♭add9 chord on piano
The A♭add9 chord, or A flat add 9, stacks 4 notes on A♭: A♭, C, E♭ and B♭. Musicians write its formula 1 3 5 9.
Notes and intervals of A♭add9
Each note of A♭add9 has a job. Counted from the root, you get root (A♭), major 3rd (C), perfect 5th (E♭) and major 9th (B♭). Change one of these intervals and you get a different chord, which is why the formula 1 3 5 9 is worth memorising rather than the shape alone.
| Degree | Interval | Note |
|---|---|---|
| 1 | root | A♭ |
| 3 | major 3rd | C |
| 5 | perfect 5th | E♭ |
| 9 | major 9th | B♭ |
How to play A♭add9 on piano
Put your right-hand thumb on A♭, then add the other notes: A♭, C, E♭ and B♭. Teachers usually suggest the fingering 1-2-3-5 (left hand: 5-3-2-1). Press the keys together, release, and repeat until the chord sounds even.
Inversions of A♭add9
An inversion keeps the same notes but puts another one in the bass. A♭add9 has 3 inversions besides root position: 1st inversion (C E♭ B♭ A♭), 2nd inversion (E♭ B♭ A♭ C) and 3rd inversion (B♭ A♭ C E♭). Inversions let you move between chords with tiny hand movements, which is how pianists make progressions sound smooth.
Which keys use A♭add9?
A♭add9 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 A♭add9
These scales share every note of A♭add9: A flat major scale, A flat major pentatonic scale, A flat Lydian mode and A flat Mixolydian mode. A flat major scale is the safest choice; the others add more colour.
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.
Spread it: left hand root and fifth, right hand 3, 5 and 9, or the 9 just below the third for a cluster that sounds lovely in the middle register. Avoid that close second low in the left hand, where it muddies. Inversions with the 9 on top give a singing melody note over the chord.
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 A♭add9 chord?
A♭add9 (A flat 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 A♭add9 on piano?
Play A♭, C, E♭ and B♭ together with the right-hand fingering 1-2-3-5. You can also play it in 3 inversions, shown on this page.
What scale goes with A♭add9?
A flat major scale fits A♭add9 best. Other scales that contain all its notes: A flat major pentatonic scale, A flat Lydian mode and A flat Mixolydian mode.
What key is A♭add9 in?
A♭add9 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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