C♯add9
C# Added 9th — a plain triad plus the ninth — colour without the seventh, clean and contemporary.
The keys
C♯ – E♯ – G♯ – D♯
What's inside C♯add9
| Note | Interval from root | Degree |
|---|---|---|
| C♯ | Root | 1 |
| E♯ | Major 3rd | 3 |
| G♯ | Perfect 5th | 5 |
| D♯ | Major 9th | 9 |
Inversions
| Position | Keys (low → high) |
|---|---|
| Root position | D♭4 – F4 – A♭4 – E♭5 |
| 1st inversion | F4 – A♭4 – E♭5 – D♭5 |
| 2nd inversion | A♭4 – E♭5 – D♭5 – F5 |
| 3rd inversion | E♭5 – D♭5 – F5 – A♭5 |
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 – A♭2 |
| Right (colour) | F4 – E♭5 |
Where C♯add9 lives
As the I chord
C♯add9 → G♭ → A♭ → C♯add9
The classic I–IV–V–I motion with this chord as home.
In a ii–V–I
E♭m7 → A♭7 → C♯add9
The strongest cadence in harmony, resolving onto this chord.
Put C♯add9 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 →