Guitar Chord A#13: Structure, Notes and Theory

A#13 — a chord built on the note “A#” with a modern, rich sound and lush harmony. Blends well with the 9 to create a complex, vivid palette. Adds freshness and depth to arrangements, especially in contrast with simple chords.

Formula and Structure of the A#13 Chord

Interval formula from the root note: 1 — 3 — 5 — b7 — 9 — 11 — 13. The chord consists of the following notes:

• Bb — unison and the main tonal anchor.
• D — major third with a bright major quality and clear stability above the tonic.
• F — perfect fifth, stabilizing the triad and adding tonal grounding.
• Ab — minor seventh with dominant pull toward the tonic.
• C — major ninth, opening the top line and adding airiness to the texture.
• Eb — eleventh with a spicy fourth above the octave, best voiced apart from the third.
• G — thirteenth with a warm sixth above the octave, sounding beautiful in the top voice.

Together, these notes form the harmonic foundation of the A#13 chord, defining its sound and role in the musical context.

Alternative Names for the A#13 Chord

There are no alternative names for this chord.

Using the A#13 Chord

Separate the 13 and 9 so they don’t clash with the 3 and b7. Place the 13 closer to the top line to give the chord a modern jazz or fusion color. Works well before resolving to the tonic or in modulations. For more expressiveness, you can omit the 5 to free space for color tones.

Conclusion

A#13 is an expressive and versatile chord. Learn several fingerings, experiment with different positions and voice spacing, then try weaving it into your own playing — this will help you quickly find your unique tone.