Build the sound
Play C – E♭ – G♭ – B𝄫 individually, then choose a shell voicing above. Sing the highest note before playing the chord.
Voicings · C°7 · Piano
C°7 voicings on piano
C°7 is spelled C – E♭ – G♭ – B𝄫 (1 ♭3 ♭5 𝄫7) — passing chords between diatonic chords, and as a 7♭9 without its root. Here are 4 ways to voice it on piano: close position, drop 2, drop 3, shell. Every diagram is playable — press play to hear the chord, or “roll it” to hear the voices one by one, low to high.
The voicings
4 ways to play C°7.
SoundRoot in gold, other voices in teal. Tap any note.
Close position
C · E♭ · G♭ · B𝄫Root, third, fifth and seventh stacked within one octave — the reference voicing (piano; too tight to finger on guitar).
Drop 2
G♭ · C · E♭ · B𝄫Take the close voicing and drop its second-highest voice an octave. The most-used four-note voicing on guitar and in piano left hands.
Drop 3
E♭ · C · G♭ · B𝄫Drop the third-highest voice of the close voicing an octave: a wide, open sound.
Shell (1–7–3)
C · B𝄫 · E♭Root, seventh and third only. The fifth is dropped — it adds nothing to the chord's identity — leaving a light, clear voicing.
Your next 10 minutes
Make C Diminished 7th part of your playing
Change the top note
Compare the displayed voicings of C°7. Notice which note is highest in each. Repeat the two shapes with the smallest comfortable hand movement, leaving a beat of silence between them.
Comp with space
Play C°7 on beats 2 and 4 at 60 bpm for four bars, then on the “and” of beat 2 for four bars. Keep the same notes while changing the rhythm. Keep the left-hand shape above the lowest octave so the voices remain clear.
Listen for this: The chord tones are C, E♭, G♭, B𝄫. passing chords between diatonic chords, and as a 7♭9 without its root. A fuller voicing is not automatically better: leave room for the melody and bass.
Understand the sound
C°7: from a pattern to a musical choice
What gives C°7 its identity?
Successive chord tones are separated by minor thirds. The seventh is a diminished seventh, not a major sixth in the chord’s theoretical spelling, even when they share a piano key.
Here the third is E♭, and degree 𝄫7 is B𝄫. Play C in the bass and compare these voices individually before combining them.
Choose a useful voicing
Start with the smallest displayed shape you can play cleanly. Move its highest note into a comfortable register and listen for a clear melody above the chord.
Separate the bass from the upper notes. If the low register sounds muddy, move the upper voices up an octave before adding more notes.
Your piano checkpoint
The black-key pitches in this collection are E♭, G♭. Use the groups of two and three black keys to orient yourself. Play C and E♭ with each hand separately before combining the hands.
Before moving on, close the diagram and name the notes: C · E♭ · G♭ · B𝄫. Then play a two-bar phrase from memory and leave two bars of silence.
Behind the voicings
Every C°7 chord tone on the keyboard.
Reference
C°7 — chord tones & function.
| Chord tone | Note | Interval |
|---|---|---|
| 1 | C | unison |
| ♭3 | E♭ | minor 3rd |
| ♭5 | G♭ | diminished 5th |
| 𝄫7 | B𝄫 | diminished 7th |
Arpeggio: C°7 arpeggio on piano. Scale: C Diminished (whole–half).
Take it to the bandstand.Practice Radio streams endless changes to comp C°7 through all twelve keys, with the chord and scale shown live — plus ear-training and call & response modes.
▶ Open Practice RadioCommon questions
C°7 voicings FAQ.
What notes are in C°7?
C, E♭, G♭, B𝄫 — chord tones 1 ♭3 ♭5 𝄫7.
What is the easiest C°7 voicing on piano?
The shell voicing: C – B𝄫 – E♭ in the left hand. Three notes that carry the whole identity of the chord.
What is a drop-2 voicing?
Start from the close voicing C E♭ G♭ B𝄫 and drop the second note from the top an octave: G♭ – C – E♭ – B𝄫. It spreads the chord so it fits the hand — and on guitar it fits four adjacent strings.
Where does C°7 appear?
C°7 is passing chords between diatonic chords, and as a 7♭9 without its root. Its character is symmetrical, restless.
Keep going
Diminished 7th voicings in every other key.
Same chord on guitar · Diminished 7th hub.
Other chords from C