Guitar Chord A#dim7: Structure, Notes and Theory

A#dim7 — a chord built on the note “A#” with a strong pull toward resolution and a symmetrical, rich quality. Effectively replaces the dominant and works well in sequential transitions.

Formula and Structure of the A#dim7 Chord

Interval formula from the root note: 1 — b3 — b5 — bb7. The chord consists of the following notes:

• Bb — unison and the main tonal anchor.
• Db — minor third with a melancholic character and gentle lyricism.
• E — diminished fifth with tritone tension, best used cautiously in the bass.
• G — double flat seventh, sounding like a sixth in modern tuning.

Together, these notes form the harmonic foundation of the A#dim7 chord, defining its sound and role in the musical context.

Alternative Names for the A#dim7 Chord

There are no alternative names for this chord.

Using the A#dim7 Chord

Emphasize minor third intervals to bring out the symmetry. Apply in sequences and for modulations. Avoid excessive density in the bass — leave some “air” below.

Conclusion

A#dim7 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.