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A augmented chord on bass (Aaug)
Also called or written Aaug or A+
A augmented contains A, C♯, and E♯. The 3rd-fret shape stacks three notes across adjacent strings, so the left hand stays compact but the stretch is real.
How it is built
Formula 1, 3, ♯5
How do you play an A augmented chord on bass?
A augmented is played at the 3rd fret as 5 4 3 ×: ring finger on the E string at fret 5, middle finger on the A string at fret 4 and index finger on the D string at fret 3. The G string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 5 | 3 | A (1) |
| 3 (A) | 4 | 2 | C♯ (3) |
| 2 (D) | 3 | 1 | E♯ (♯5) |
| 1 (G) | muted | — | — |
IntermediateThe ring finger reaches to the 5th fret on the E string while the index stays at the 3rd fret on the D string, creating a two-fret stretch.
10th fret
A augmented is played at the 10th fret as × 12 11 10: ring finger on the A string at fret 12, middle finger on the D string at fret 11 and index finger on the G string at fret 10. The E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | muted | — | — |
| 3 (A) | 12 | 3 | A (1) |
| 2 (D) | 11 | 2 | C♯ (3) |
| 1 (G) | 10 | 1 | E♯ (♯5) |
Aaug/C♯ inversion · fret 2
A augmented is played at the 2nd fret as × 4 3 2: ring finger on the A string at fret 4, middle finger on the D string at fret 3 and index finger on the G string at fret 2. The E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | muted | — | — |
| 3 (A) | 4 | 3 | C♯ (3) |
| 2 (D) | 3 | 2 | E♯ (♯5) |
| 1 (G) | 2 | 1 | A (1) |
Aaug/C♯ inversion · fret 7
A augmented is played at the 7th fret as 9 8 7 ×: ring finger on the E string at fret 9, middle finger on the A string at fret 8 and index finger on the D string at fret 7. The G string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | 9 | 3 | C♯ (3) |
| 3 (A) | 8 | 2 | E♯ (♯5) |
| 2 (D) | 7 | 1 | A (1) |
| 1 (G) | muted | — | — |
Aaug/E♯ inversion
A augmented is played at the 6th fret as × 8 7 6: ring finger on the A string at fret 8, middle finger on the D string at fret 7 and index finger on the G string at fret 6. The E string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 4 (E) | muted | — | — |
| 3 (A) | 8 | 3 | E♯ (♯5) |
| 2 (D) | 7 | 2 | A (1) |
| 1 (G) | 6 | 1 | C♯ (3) |
Why it sounds like that
A augmented is built from the formula 1, 3, ♯5. The augmented 5th from A to E♯ gives the chord its tense, unresolved quality. Compare it with A major, which lowers that fifth to E natural.
What goes wrong with A augmented?
- Letting the ring finger flatten onto the A string, which deadens the C♯.
- Allowing the open G string to ring, adding a note outside the chord.
- Pressing the middle finger too far from the fret, causing the A string to buzz.
When to use it
A augmented works as a passing chord in A major, often moving to A major or A 5th. Its unstable sound suits rock, blues, and funk lines that need a brief lift before resolving.
Changing to and from A augmented
- Move to A major by lowering the E♯ on the D string one fret to E natural while keeping the other fingers in place.
- Slide the shape down two frets to the 1st fret to reach G augmented.
Which voicing to use
The 3rd-fret position keeps A in the bass for a root-position sound. The Aaug/C♯ inversion at the 2nd fret puts C♯ on the bottom, which softens the chord's drive and works well when the bass line moves stepwise.
Other A chords
Common questions
How is A augmented written?
A augmented is written as A+ or Aaug.
What is the difference between A augmented and A major?
A augmented raises the fifth from E to E♯. That single change makes the chord sound tense and unresolved, while A major sounds stable.
Can I play A augmented higher on the neck?
Yes, the 10th-fret position uses the same shape on the A, D, and G strings. It gives a brighter register but the same chord tones.