Map it slowly
Locate C, B𝄫 on white keys and E♭, G♭ on black keys. Try each hand separately before playing together; choose a fingering that keeps the wrist relaxed, without stretching between notes.
Arpeggio · C°7 · Piano
C°7 arpeggio on piano
The C°7 arpeggio is C – E♭ – G♭ – B𝄫 — chord tones 1 ♭3 ♭5 𝄫7. C°7 is passing chords between diatonic chords, and as a 7♭9 without its root; its sound is symmetrical, restless. Below, every C, E♭, G♭, B𝄫 on the two-octave keyboard is marked, with the root in gold. Press play to hear a one-octave arpeggio, or tap any note.
Visualizer
C°7 on the keyboard.
Piano
Guitar · standard tuning
RootChord toneBeing played
Tempo100 bpm
Show
Sound
Play loops the arpeggio up and down one octave (switch Loop off for a single pass). Tap any marked note to hear it. “Show” switches or combines the fretboard and keyboard; “Sound” picks the instrument you hear. Audio is synthesized in the browser.
Your next 10 minutes
Make C Diminished 7th part of your playing
Make a short phrase
Play C – E♭ – G♭ – B𝄫 in quarter notes at 60 bpm. Repeat starting from E♭, wrapping back to C. Do not speed up until every attack is even.
Hear it in context
Alternate E♭ and B𝄫 above a sustained C. These are degree ♭3 and 𝄫7. End a four-bar phrase on either one instead of always returning to the root.
Listen for this: C°7 has the colour “symmetrical, restless”. Name the degrees as you play, so you can recognize the sound in another key rather than remembering only a shape.
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.
Turn the arpeggio into a melody
Try E♭ – G♭ – B𝄫 – C as quarter notes, then repeat the first note and omit the last. The second phrase uses the same harmony with a different shape.
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.
On guitar
C°7 on the fretboard.
Reference
C°7 — chord tones & intervals.
| Chord tone | Note | Interval from C |
|---|---|---|
| 1 | C | unison (0 semitones) |
| ♭3 | E♭ | minor 3rd (3 semitones) |
| ♭5 | G♭ | diminished 5th (6 semitones) |
| 𝄫7 | B𝄫 | diminished 7th (9 semitones) |
Goes with: C Diminished (whole–half) (C D E♭ F G♭ A♭ A B). Voicings: C°7 voicings on piano.
Take it to the bandstand.Practice Radio streams endless changes to play the C°7 arpeggio over through all twelve keys, with the chord and scale shown live — plus ear-training and call & response modes.
▶ Open Practice RadioCommon questions
C°7 arpeggio FAQ.
What notes are in a C°7 arpeggio?
C – E♭ – G♭ – B𝄫. As chord tones: 1 ♭3 ♭5 𝄫7. Played one after another instead of together, that is the arpeggio.
What is a C°7 chord used for?
C°7 is passing chords between diatonic chords, and as a 7♭9 without its root. Its character is symmetrical, restless.
Which scale goes with C°7?
C Dim. W–H (C D E♭ F G♭ A♭ A B) — the arpeggio is the skeleton of that scale, so practise them together.
How do I practise the C°7 arpeggio on piano?
Play C – E♭ – G♭ – B𝄫 ascending from C, then descend; then start from each chord tone in turn (inversions) so your hand knows the shape from any note.
Keep going
Diminished 7th arpeggio in every other key.
Same arpeggio on guitar · Diminished 7th hub · chord-scale theory.
Other arpeggios from C