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A♭ 9th chord on guitar (A♭9)
Also called or written A♭9 or A♭
A♭ 9th is built from A♭, C, E♭, G♭, and B♭. This advanced barre chord demands clean fretting across five strings while muting the high E.
How it is built
Formula 1, 3, 5, ♭7, 9
- Root positionA♭–C–E♭–G♭–B♭A♭94-3-4-3-4-×
- First inversionC–E♭–G♭–B♭–A♭A♭9/C×-3-4-3-4-4
- Second inversionE♭–G♭–B♭–A♭–CA♭9/E♭no shape on this instrument
- Third inversionG♭–B♭–A♭–C–E♭A♭9/G♭2-1-1-1-1-2
- Fourth inversionB♭–A♭–C–E♭–G♭A♭9/B♭×-1-1-1-1-2
How do you play an A♭ 9th chord on guitar?
A♭ 9th is played at the 3rd fret as 4 3 4 3 4 ×: barre your index finger across fret 3, middle finger on the low E string at fret 4, ring finger on the D string at fret 4 and pinky finger on the B string at fret 4. The high e string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 4 | 2 | A♭ (1) |
| 5 (A) | 3 | 1 (barre) | C (3) |
| 4 (D) | 4 | 3 | G♭ (♭7) |
| 3 (G) | 3 | 1 (barre) | B♭ (2) |
| 2 (B) | 4 | 4 | E♭ (5) |
| 1 (e) | muted | — | — |
AdvancedThe index barre must hold the 5th and 3rd strings at the 3rd fret while the pinky stretches to the 2nd string, 4th fret.
4th fret
A♭ 9th is played at the 4th fret as 4 6 4 5 4 6: barre your index finger across fret 4, ring finger on the A string at fret 6, middle finger on the G string at fret 5 and pinky finger on the high e string at fret 6.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 4 | 1 (barre) | A♭ (1) |
| 5 (A) | 6 | 3 | E♭ (5) |
| 4 (D) | 4 | 1 (barre) | G♭ (♭7) |
| 3 (G) | 5 | 2 | C (3) |
| 2 (B) | 4 | 1 (barre) | E♭ (5) |
| 1 (e) | 6 | 4 | B♭ (2) |
A♭9/C inversion · fret 3
A♭ 9th is played at the 3rd fret as × 3 4 3 4 4: barre your index finger across fret 3, middle finger on the D string at fret 4, ring finger on the B string at fret 4 and pinky finger on the high e string at fret 4. The low E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | muted | — | — |
| 5 (A) | 3 | 1 (barre) | C (3) |
| 4 (D) | 4 | 2 | G♭ (♭7) |
| 3 (G) | 3 | 1 (barre) | B♭ (2) |
| 2 (B) | 4 | 3 | E♭ (5) |
| 1 (e) | 4 | 4 | A♭ (1) |
A♭9/C inversion · fret 6
A♭ 9th is played at the 6th fret as 8 6 6 8 7 6: barre your index finger across fret 6, ring finger on the low E string at fret 8, pinky finger on the G string at fret 8 and middle finger on the B string at fret 7.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 8 | 3 | C (3) |
| 5 (A) | 6 | 1 (barre) | E♭ (5) |
| 4 (D) | 6 | 1 (barre) | A♭ (1) |
| 3 (G) | 8 | 4 | E♭ (5) |
| 2 (B) | 7 | 2 | G♭ (♭7) |
| 1 (e) | 6 | 1 (barre) | B♭ (2) |
A♭9/C inversion · fret 8
A♭ 9th is played at the 8th fret as 8 9 8 8 9 8: barre your index finger across fret 8, ring finger on the A string at fret 9 and pinky finger on the B string at fret 9.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 8 | 1 (barre) | C (3) |
| 5 (A) | 9 | 3 | G♭ (♭7) |
| 4 (D) | 8 | 1 (barre) | B♭ (2) |
| 3 (G) | 8 | 1 (barre) | E♭ (5) |
| 2 (B) | 9 | 4 | A♭ (1) |
| 1 (e) | 8 | 1 (barre) | C (3) |
Why it sounds like that
A♭ 9th stacks a major 3rd, perfect 5th, minor 7th, and major 2nd above the root. The minor 7th gives it dominant pull, while the major 2nd adds color. Compare it to the plain A♭ 7th, which omits the 9th.
What goes wrong with A♭ 9th?
- Letting the 1st string sound open instead of muting it with the side of the index finger.
- Buzzing on the 3rd string because the index barre isn't pressing hard enough.
- Allowing the pinky to flatten and deaden the 1st string when fretting the 2nd string.
Changing to and from A♭ 9th
- Slide the shape down one fret to the 2nd fret to play G 9th, keeping the same finger pattern.
- Move to A 9th by sliding the entire shape up one fret to the 4th fret.
Which voicing to use
The 3rd fret voicing keeps A♭ in the bass for a root-position sound. The A♭9/C inversions put C in the bass, creating a lighter, less grounded feel. Choose the 4th fret voicing for a fuller register.
Other A♭ chords
Common questions
How is A♭ 9th written?
A♭ 9th is written as A♭9 or A♭. On a keyboard, type Ab9. It is also spelled G♯ in enharmonic notation for the same sounding root.
What is the difference between A♭ 9th and A♭ 7th?
A♭ 9th adds the 9th (B♭) to the A♭ 7th chord. The 9th creates a richer, more colorful dominant sound.
Why is the high E string muted in the 3rd fret voicing?
The open high E is not a chord tone in A♭ 9th. Muting it keeps the chord clean and prevents an unwanted note.
Can A♭ 9th be played without a barre?
The 3rd fret voicing requires a barre across five strings. Other inversions also use barres, so this chord is best for players comfortable with barre technique.