Explore the A#9 Guitar Chord: Play & Master Its Sound
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The A#9 chord is A# dominant ninth, spelled A#, C##, E#, G# and B#. It sounds the same as Bb9, which has easier notes (Bb, D, F, Ab and C), so charts usually print that name.
Three voicings are listed, one with an open string and one with a barre, the lowest at the 1st fret. The double sharp and the B# are theoretical spellings that appear only because the root is sharp. The A# Mixolydian scale contains every tone.
Press play above to listen to the chord strummed and then arpeggiated.
A# dominant 9th guitar chord is also written as A#9, A#dom9, A#7(9) or A#7add9.
A# 9 chord Notes:
Tones in the Dominant Ninth chord:
Formula: 1 3 5 b7 9
A# 9 Guitar Chord Diagrams
Position 1 Open
Finger Positions
- Mute the low E string
- Let the D string play without pressing any fret
- Mute the high E string
- Place your middle finger (2) on the fret 1 of the A string
- Place your ring finger (3) on the fret 1 of the G string
- Place your pinky finger (4) on the fret 1 of the B string
Position 2 Movable
Finger Positions
- Mute the low E string
- Mute the high E string
- Place your index finger (1) on the fret 5 of the A string
- Place your middle finger (2) on the fret 5 of the G string
- Place your ring finger (3) on the fret 6 of the D string
- Place your pinky finger (4) on the fret 6 of the B string
Position 3 Barre Movable
Finger Positions
- Mute the A string
- Place your index finger (1) on the fret 6 of the low E, D and B strings at the same time
- Place your middle finger (2) on the fret 7 of the G string
- Place your pinky finger (4) on the fret 8 of the high E string
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Created by
Giancarlo is a musician (teaching guitar since 2000), software engineer, AI consultant and published researcher
FAQ
What notes are in A# dominant ninth?
A#9 is spelled A#, C##, E#, G# and B#. It stacks the A#7 notes with a B# on top, a major ninth over the root.
Is A#9 the same as Bb9?
Yes. Bb9 spells the same five pitches as Bb, D, F, Ab and C, which avoids the double sharp and the E# and B# that A#9 requires.
Why does A# dominant ninth need a double sharp?
The major third has to be some kind of C, and C# would only make a minor third over A#. So it is written C##, which sounds like D.
What does the 9 in A#9 stand for?
It is the B#, a major ninth over A#, which is the second degree of the scale placed an octave higher. Written as B#, it sounds like C.
How many voicings does A#9 offer?
There are 3 voicings, from fret 1 to fret 8. One has an open string and one is a barre voicing.
