C#aug9 guitar chord
The standard grips this chord is usually shown with.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About C#aug9 — root position
C#aug9 is C#, E#, A, B and D# — C#7 with the fifth raised and the natural ninth added on top.
It sounds bright, tense and slightly unreal. Raising the fifth leaves no semitone in the lower half of the chord, which is where the whole-tone flavour comes from.
C#aug9 notes and formula
| C# | E# | A | B | D# |
|---|---|---|---|---|
| 1 | 3 | ♯5 | ♭7 | 9 |
Altered dominant — dominant pull with a whole-tone colour.
Also written C#9#5, C#+9 or C#9(#5). The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C#aug9
C#aug9 in root position puts C# in the bass, which is the chord as it is spelled: the note it is named after underneath everything else.
5 of C#aug9’s 9 common shapes do this: x43445, 98780x, 9-8-9-8-10-x, 9-12-9-10-0-11, 9-x-9-10-10-11.
Start with 98780x — no barre and 1 open string. None of the shapes for C#aug9 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 9 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 121221 | 1st fret | E#, 1st inversion | E# | barred |
| x43445 | 3rd fret | C#, root position | A | barred |
| 767667 | 6th fret | B, 3rd inversion | B | barred |
| 98780x | 7th fret | C#, root position | D# | 1 open string |
| 9-8-9-8-10-x | 8th fret | C#, root position | A | all fretted |
| 9-12-9-10-0-11 | 9th fret | C#, root position | D# | 1 open string |
| 9-x-9-10-10-11 | 9th fret | C#, root position | D# | all fretted |
| x-x-9-10-10-11 | 9th fret | B, 3rd inversion | D# | all fretted |
| 13-14-13-14-14-13 | 13th fret | E#, 1st inversion | E# | barred |
The same notes rebuilt from scratch give 5 shell and 13 rootless voicings, each on its own page.
Tensions. A shell of C#aug9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (F##).
How to use C#aug9
C#aug9 is a dominant with its tension raised, so it still points at F# — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
Voice by voice, C#aug9 → F#. 3 voices move by a semitone, and one note is common to both chords.
| In C#aug9 | Moves | In F# |
|---|---|---|
| C#, the root | stays where it is | C#, the fifth |
| E#, the major third | rises a semitone | F#, the root |
| A, the sharp fifth | rises a semitone | A#, the major third |
| B, the flat seventh | falls a semitone | A#, the major third |
| D#, the ninth | falls a whole tone | C#, the fifth |
What to play over C#aug9
Every note of C#aug9 is in C# whole tone.
Chords near C#aug9
Change one note of C#aug9 and you have C#alt (the ninth becomes a flat ninth), C#aug7 (drop the ninth), C#9 (the sharp fifth becomes a fifth) or C#9b5 (the sharp fifth becomes a flat fifth).
C#aug9 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On C#aug9’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.