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Note identifier · Reference entry

What chord is C–E♭–F♯–B♭?

The notes C, E♭, F♯, and B♭ spell C Half Diminished (Cm7♭5) — C the root, E♭ the ♭3, G♭ the ♭5, and B♭ the ♭7.

Ranked readings

Every chord these notes can spell, most complete first. The bass note anchors the root-position reading; each candidate maps every note to its scale degree.

C Half DiminishedCm7♭5Confident

Every tone of Cm7♭5 is present, with C in the bass — the definitive reading.

DegreeNoteIn this set
1Csounding
♭3E♭sounding
♭5G♭sounding
♭7B♭sounding
E♭ Minor 6thE♭m6Confident

All tones of E♭m6 are present; the C note is lowest (3rd inversion).

DegreeNoteIn this set
1E♭sounding
♭3G♭sounding
5B♭sounding
6Csounding

3rd, 5th, ♭7, and 9th of A♭9 sound; it reads as A♭9 with the A♭ (1) omitted.

DegreeNoteIn this set
1A♭omitted
3Csounding
5E♭sounding
♭7G♭sounding
9B♭sounding

Not these chords

Names these notes are often mistaken for. Each is ruled out because a defining tone of that chord is missing — the note that would make the name true simply is not being played.

Not C7♭5♯9

Not C7♭5♯9: a dominant 7th ♭5 ♯9 C chord needs E as its 3rd — E is absent.

Not Cdim7

Not Cdim7: a diminished 7th C chord needs B♭♭ as its ♭♭7 — B♭♭ is absent.

Not E♭dim7

Not E♭dim7: a diminished 7th E♭ chord needs B♭♭ as its ♭5 — B♭♭ is absent.

Not F♯dim7

Not F♯dim7: a diminished 7th F♯ chord needs A as its ♭3 — A is absent.

Not C7♭5

Not C7♭5: a dominant 7th ♭5 C chord needs E as its 3rd — E is absent.

How these notes relate

C, E♭, F♯, and B♭ is a voicing of A♭9 with the A♭ (root) left out.

The same notes over E♭ in the bass spell E♭m6.

Add E (its 3rd) and the set reads as C7♭5♯9.

Set-class analysis

The pitch-class set theory identity of these notes — order- and key-independent, computed from the set itself.

Pitch-class set
{0, 3, 6, 10}
Normal order
[10,0,3,6]
Prime form
[0,2,5,8]
Interval vector
<012111>
Forte set class
4-27

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