C#m7b5 guitar chord
Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About C#m7b5 — shell voicings
C#m7b5 is C#, E, G and B — C#m7 with the fifth lowered a semitone.
It sounds hollow, and unmistakably going somewhere. Almost always the first chord of a minor ii–V–i, so it walks straight into an altered dominant.
C#m7b5 notes and formula
| C# | E | G | B |
|---|---|---|---|
| 1 | ♭3 | ♭5 | ♭7 |
Pre-dominant — the ii of a minor key.
Also written C#ø, C#ø7, C#m7-5, C#m7(b5) or C# half diminished. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C#m7b5
Root, third and seventh. The third and seventh, the guide tones, are what make the chord major, minor or dominant, so the fifth can go: it says nothing the symbol needs.
Three notes means a spare string, which is the real point. Put a tension on it.
C#m7b5 has 5 of them, on strings 5-3-2-1, strings 6-4-3-2, the middle four strings and the bottom four strings, from the 3rd fret up to the 9th — all in one inversion, so the bass note never moves. The one to learn first is the C# shape at the 3rd fret.
Start with x4545x — no barre and low, at the 4th fret. None of the shapes for C#m7b5 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 3 of the 7 need a barre. Together they cover the neck from the 2nd fret to the 12th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x42423 | 2nd fret | C#, root position | G | all fretted |
| x4545x | 4th fret | C#, root position | E | all fretted |
| xx5657 | 5th fret | G, 2nd inversion | B | all fretted |
| 9xx987 | 7th fret | C#, root position | B | all fretted |
| 9x998x | 8th fret | C#, root position | G | barred |
| 9-10-11-9-12-9 | 9th fret | C#, root position | C# | barred |
| x-x-11-12-12-12 | 11th fret | C#, root position | E | barred |
The same notes rebuilt from scratch give 13 drop 2, 9 drop 3 and 6 open string voicings, each on its own page.
Tensions. A shell of C#m7b5, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (F#) and the b13 (A).
How to use C#m7b5
C#m7b5 is the ii of B minor, which is where it is nearly always found: half-diminished, then an altered dominant, then the minor tonic.
In which keys. Every note of C#m7b5 belongs to D major (the vii°, the leading tone) and B minor (the ii°, the supertonic).
What to play over C#m7b5
Every note of C#m7b5 is in C# blues, C# locrian, C# altered and C# half-whole diminished.
Chords near C#m7b5
Change one note of C#m7b5 and you have C#dim (drop the flat seventh), C#dim7 (the flat seventh becomes a sixth), C#m7 (the flat fifth becomes a fifth), C#mMaj7b5 (the flat seventh becomes a major seventh) or C#7b5 (the minor third becomes a major third).
C#m7b5 is a diminished chord — root, minor third, flat fifth. Diminished and half-diminished chords on every root.
On C#m7b5’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.