About C#7sus4 — drop 2 voicings
C#7sus4 is C#, F#, G# and B — C#7 with the third replaced by the fourth.
It sounds leaning rather than shoving. It keeps the flat seventh’s pull and loses the tritone, so it moves without making a hard cadence.
C#7sus4 notes and formula
| C# | F# | G# | B |
|---|---|---|---|
| 1 | 4 | 5 | ♭7 |
Dominant — it points a fifth down, but softly.
Also written C#7sus or C# dominant 7 sus 4. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C#7sus4
Take the four notes stacked as close together as they go, then drop the second voice from the top an octave. The gap it opens is what makes the chord sound like a chord rather than a cluster.
It lands on four adjacent strings, which is why it is the workhorse voicing on guitar.
C#7sus4 has 12 of them, on the top four strings, the bottom four strings and the middle four strings, from open position up to the 11th — every inversion the chord has: C# in the bass, F# in the bass, G# in the bass and B in the bass. The one to learn first is the F# shape at the 2nd fret, which is the easiest grip here.
4 of them sit on the top four strings, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with xxx677 — no barre and only 3 fretted notes. None of the shapes for C#7sus4 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 3 of the 6 need a barre. Together they cover the neck from the 2nd fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x44422 | 2nd fret | C#, root position | F# | barred |
| x46474 | 4th fret | C#, root position | G# | barred |
| xxx677 | 6th fret | C#, root position | B | all fretted |
| xx6677 | 6th fret | G#, 2nd inversion | B | all fretted |
| 9-11-9-11-9-9 | 9th fret | C#, root position | C# | barred |
| x-x-11-13-12-14 | 11th fret | C#, root position | F# | all fretted |
The same notes rebuilt from scratch give 5 shell and 9 drop 3 voicings, each on its own page.
Tensions. A shell of C#7sus4, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (D#) and the 13 (A#).
How to use C#7sus4
Voice by voice, C#7sus4 → F#. One voice moves by a semitone, and 2 notes are common to both chords.
| In C#7sus4 | Moves | In F# |
|---|---|---|
| C#, the root | stays where it is | C#, the fifth |
| F#, the fourth | stays where it is | F#, the root |
| G#, the fifth | falls a whole tone | F#, the root |
| B, the flat seventh | falls a semitone | A#, the major third |
In which keys. Every note of C#7sus4 belongs to C# minor (the i), Eb minor (the ♭VII), E major (the vi), F# major (the V), F# minor (the v), Ab minor (the iv), A major (the iii) and B major (the ii).
What to play over C#7sus4
Every note of C#7sus4 is in C# minor pentatonic, C# blues, C# mixolydian, C# dorian and C# natural minor.
Chords near C#7sus4
Change one note of C#7sus4 and you have C#sus4 (drop the flat seventh), C#sus2sus4 (the flat seventh becomes a ninth), C#m7 (the fourth becomes a minor third) or C#7 (the fourth becomes a major third).
C#7sus4 is a suspended chord — root and fifth, with a second or fourth where the third would be — or nothing at all. Suspended and power chords on every root.
On C#7sus4’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.