Finger Positions

Root Note C#

Name C# dominant flat ninth over A#

Intervals 1P-3M-5P-7m-9m

Relative Minor A#m

Notes A#, C#, F, G#, B, D

Aliases C#7b9

How to play the C#7b9/A# Chord

The C#7b9/A# is a fundamental dominant chord in guitar music. To play this chord correctly, ensure your fingers are placed precisely on the frets indicated in the diagram above.

Music Theory Analysis

From a theoretical perspective, the C# dominant flat ninth over A# is built using the 1P, 3M, 5P, 7m, 9m intervals. In the key of C# Major, this chord functions as the I chord.

Common Progressions

In music composition, the C#7b9/A# chord is often used to create tension or resolution.

I-V-vi-IV

C# → G# → A#m → F#

vi-IV-I-V

A#m → F# → C# → G#

The Diatonic Family

Understanding the "family" of chords that belong to C# helps with transposition and ear training.

Triads

C# D#m Fm F# G# A#m Cdim

7ths

C#maj7 D#m7 Fm7 F#maj7 G#7 A#m7 Cm7b5

Scale Compatibility

View All Scales

Phrygian Dominant Flamenco Spanish Heptatonic Half-Whole Diminished Chromatic

* 5 scales found containing the notes A#, C#, F, G#, B, D.

Acoustic & Digital Analysis

Digital footprint of the C#7b9/A# chord for MIDI programming and synthesizer sound design.

MIDI Numbers 70, 61, 65, 68, 71, 62

Frequencies (Hz)

466.1637615180899, 277.1826309768721, 349.2282314330039, 415.3046975799451, 493.8833012561241, 293.6647679174076