The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped.
C7sus4 is C, F, G and Bb — C7 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 | F | G | Bb |
|---|---|---|---|
| 1 | 4 | 5 | ♭7 |
Dominant — it points a fifth down, but softly.
Also written C7sus or C dominant 7 sus 4. The same chord either way; which spelling you meet depends on who wrote the chart.
The same operation one voice further down: the third voice from the top falls an octave and becomes the bass.
That leaves a bigger hole under the top three notes, so a string gets skipped: the muted string in the middle is the shape, not a mistake.
C7sus4 has 10 of them, on strings 6-4-3-2 and strings 5-3-2-1, from open position up to the 13th — every inversion the chord has: C in the bass, F in the bass, G in the bass and Bb in the bass. The one to learn first is the G shape at the nut.
5 of them sit on strings 6-4-3-2, 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 xxx566 — no barre and only 3 fretted notes. None of the shapes for C7sus4 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 7 need a barre. Together they cover the neck from the 1st fret to the 15th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x33311 | 1st fret | C, root position | F | barred |
| x35363 | 3rd fret | C, root position | G | barred |
| xxx566 | 5th fret | C, root position | Bb | all fretted |
| xx5566 | 5th fret | G, 2nd inversion | Bb | all fretted |
| 8-10-8-10-8-8 | 8th fret | C, root position | C | barred |
| x-x-10-12-11-13 | 10th fret | C, root position | F | all fretted |
| x-15-15-15-13-13 | 13th fret | C, root position | F | barred |
The same notes rebuilt from scratch give 7 shell, 15 drop 2 and 1 open string voicings, each on its own page.
Tensions. A shell of C7sus4, root, third and seventh, leaves a string free, and the tones that belong over it are the 9 (D) and the 13 (A).
Voice by voice, C7sus4 → F. One voice moves by a semitone, and 2 notes are common to both chords.
| In C7sus4 | 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 |
| Bb, the flat seventh | falls a semitone | A, the major third |
In which keys. Every note of C7sus4 belongs to C minor (the i), D minor (the ♭VII), Eb major (the vi), F major (the V), F minor (the v), G minor (the iv), Ab major (the iii) and Bb major (the ii).
Every note of C7sus4 is in C minor pentatonic, C blues, C mixolydian, C dorian and C natural minor.
Change one note of C7sus4 and you have Csus4 (drop the flat seventh), Csus2sus4 (the flat seventh becomes a ninth), Cm7 (the fourth becomes a minor third), C7 (the fourth becomes a major third), C7/G (the fourth becomes a major third) or C11 (add the ninth).
C7sus4 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 C7sus4’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.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.