The short version
- A9 is A ninth. Its notes are A, C♯, E, G and B (formula 1 – 3 – 5 – ♭7 – 9).
- Easiest way to play it: the open shape, frets x 0 2 4 2 3 from low E to high E (x = don’t play).
- It sounds funky, bluesy and slick. Vamp on it with short, choppy strums for funk, or use it as a fancier V7 in blues and soul.
- A9 turns up in 2 keys: D major (as the V9) and B minor (as the VII9).
- Try it in: A9 – D9 – A9 – D9, a two-chord funk vamp: short strums, lots of attitude.
How to play A9 on guitar, step by step
Start with the shape marked “Start here” above: the open chord, the easiest way in.
- Put your index finger on fret 2 of the 4th (D) string.
- Put your middle finger on fret 2 of the 2nd (B) string.
- Put your ring finger on fret 3 of the 1st (high E) string.
- Put your little finger on fret 4 of the 3rd (G) string.
- Let the A string ring open.
- Don’t play the low E string: skip it, or touch it lightly with a spare finger so it can’t ring.
- Strum from the 5th (A) string down, then press Strum on this page to check it sounds the same.
Once that’s comfy, try the other shape. Shape 2 is the barre chord, root on the 6th string (5th fret): 5 7 5 6 5 7. Same chord, different spot on the neck, which helps when the next chord lives nearby.
Buzzing? Press just behind the fret wire, not in the middle of the fret, and come down on your fingertips so they don’t touch the next string. Then press Strum and play along: if yours sounds duller, one string is muted somewhere.
Notes in the A9 chord
A9 is built from 5 notes. On guitar you’ll often play some of them twice, on different strings. That’s normal; the chord is still A9.
| Note | Interval | What it does |
|---|---|---|
| A | 1 root | Names the chord and anchors the bass. |
| C♯ | 3 major third | Makes it major (happy). |
| E | 5 perfect fifth | Adds weight; often the first note left out. |
| G | ♭7 minor (flat) seventh | The bluesy pull towards the next chord. |
| B | 9 ninth | Sparkle on top. |
What A9 sounds like, and when to use it
A dominant seventh with the ninth stacked on top. Funky. James Brown’s guitarists basically lived on one of these for a decade. Vamp on it with short, choppy strums for funk, or use it as a fancier V7 in blues and soul.
What key is A9 in?
A9 turns up in 2 keys: D major (as the V9) and B minor (as the VII9). Tap a key to see the rest of its chords on the circle of fifths.
| Key | Numeral | Spelled as |
|---|---|---|
| D major | V9 | A9 |
| B minor | VII9 | A9 |
Chords that go with A9
Here’s a progression to try: A9 – D9 – A9 – D9 (I9–IV9), a two-chord funk vamp: short strums, lots of attitude.
More progressions → Transpose it →
Using A9 in a Suno prompt
Suno pays attention to chord names in a style prompt, at least some of the time. Put the progression in, keep the BPM, and let it fill in the rest. Then compare its guitar part with the shapes above.
Funk, 108 BPM, chord progression A9 – D9 – A9 – D9, choppy ninth-chord guitar stabs, slap bass, tight funky drums, horn hits, groovy and playful
A9 chord FAQ
What notes are in the A9 chord?
A9 has 5 notes: A (the root), C♯ (the major third), E (the perfect fifth), G (the minor (flat) seventh) and B (the ninth). The chord formula is 1 – 3 – 5 – ♭7 – 9.
How do you play A9 on guitar?
The easy way is open chord. Strings from low E to high E: x 0 2 4 2 3 (x means don’t play that string). Put your index finger on fret 2 of the 4th (D) string. Put your middle finger on fret 2 of the 2nd (B) string. Put your ring finger on fret 3 of the 1st (high E) string. Put your little finger on fret 4 of the 3rd (G) string. Let the A string ring open. Don’t play the low E string: skip it, or touch it lightly with a spare finger so it can’t ring.
What does the “9” in A9 mean?
It tells you the chord type: A9 is A ninth. A dominant seventh with the ninth stacked on top. Funky. James Brown’s guitarists basically lived on one of these for a decade.
What key is A9 in?
A9 turns up in 2 keys: D major (as the V9) and B minor (as the VII9). Major keys: D major. Minor keys: B minor.
What is the difference between A9 and A7?
A9 is A7 with the ninth (B) on top. It sounds richer and funkier; A7 is the plainer, bluesier version.
What chords go well with A9?
Try D9, A7, D and E9. The progression A9 – D9 – A9 – D9 (I9–IV9) is a two-chord funk vamp: short strums, lots of attitude. Press Play progression on this page to hear it.
Other dominant 9th chords
Got the chord? Now write the song
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