C♯7♭9
C# Dominant 7th Flat 9 — a dominant with a dark flattened ninth — sharp tension that resolves with real drama, especially into minor.
The keys
C♯ – E♯ – G♯ – B – D
What's inside C♯7♭9
| Note | Interval from root | Degree |
|---|---|---|
| C♯ | Root | 1 |
| E♯ | Major 3rd | 3 |
| G♯ | Perfect 5th | 5 |
| B | Minor 7th | b7 |
| D | Flat 9th | b9 |
A working voicing
Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:
| Hand | Keys |
|---|---|
| Left (shell) | D♭2 – B2 |
| Right (colour) | F4 – D5 |
Where C♯7♭9 lives
Hard resolution
C♯7♭9 → G♭m9
Altered dominants resolve with maximum drama — especially into minor.
Chromatic approach
A♭m7 → C♯7♭9 → G♭
The alteration sharpens the pull of the standard two-five.
Put C♯7♭9 under your fingers
Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.
Open the Chord & Voicing Lab →