# C Minor 9th piano chord (Cm9) Cm9 contains C, E♭, G, B♭ and D. A minor seventh with the ninth added on top. E♭ and B♭ are black keys; C, G and D are white. - Canonical page: https://piano.org/chords/minor-9th/c/ - Entity: chord:minor-9th:c - Notes: C E♭ G B♭ D - Formula: 1 ♭3 5 ♭7 9 - Intervals from root: P1, m3, P5, m7, M9 - Interval stack (semitones): 3 4 3 4 - Also written: Cm9, Cm9, C minor 9th - Parameters: A440, 12-TET, 165 mm octave, spans centre to centre ## Construction | Degree | Note | Interval from root | Semitones | | --- | --- | --- | --- | | 1 | C | Perfect unison | 0 | | ♭3 | E♭ | Minor third | 3 | | 5 | G | Perfect fifth | 7 | | ♭7 | B♭ | Minor seventh | 10 | | 9 | D | Major ninth | 14 | ## Fingering Rest your right hand over the notes with finger 1 on C, finger 2 on E♭, finger 3 on G, finger 4 on B♭, finger 5 on D. The left hand mirrors it. Right hand 1-2-3-4-5, left hand 5-4-3-2-1. Source: piano.org fingering method v1. ## Inversions | Position | Bass | Notes in order | Figured bass | Span | | --- | --- | --- | --- | --- | | Root position | C | C3 E♭3 G3 B♭3 D4 | 9 | 14 st, 193 mm | | First inversion (Cm9/E♭) | E♭ | E♭3 G3 B♭3 C4 D4 | 7/6/5 | 11 st, 151 mm | | Second inversion (Cm9/G) | G | G3 B♭3 C4 D4 E♭4 | 7/4/3 | 8 st, 110 mm | | Third inversion (Cm9/B♭) | B♭ | B♭3 C4 D4 E♭4 G4 | 7/4/2 | 9 st, 124 mm | | Fourth inversion (Cm9/D) | D | D3 E♭3 G3 B♭3 C4 | 9/7/5 | 10 st, 138 mm | ## Voicings (11) | Voicing | Notes | Span | Relation | Omits or adds | | --- | --- | --- | --- | --- | | Close, root position | C3 E♭3 G3 B♭3 D4 | 14 st, 193 mm | identical | none | | Close, first inversion | E♭3 G3 B♭3 C4 D4 | 11 st, 151 mm | identical | none | | Close, second inversion | G3 B♭3 C4 D4 E♭4 | 8 st, 110 mm | identical | none | | Close, third inversion | B♭3 C4 D4 E♭4 G4 | 9 st, 124 mm | identical | none | | Close, fourth inversion | D3 E♭3 G3 B♭3 C4 | 10 st, 138 mm | identical | none | | Drop 2 | B♭2 C3 E♭3 G3 D4 | 16 st, 220 mm | identical | none | | Drop 3 | G2 C3 E♭3 B♭3 D4 | 19 st, 261 mm | identical | none | | Drop 2 and 4 | E♭2 B♭2 C3 G3 D4 | 23 st, 316 mm | identical | none | | Shell, root 9 ♭3 | C2 D3 E♭3 | 15 st, 206 mm | subset | omits G | | Guide tones, ♭3 and 9 | E♭3 D4 | 11 st, 151 mm | subset | omits C and G | | Rootless close | E♭3 G3 B♭3 D4 | 11 st, 151 mm | subset | omits C | ## One-edit neighbors | Becomes | Edit | Changes | Common tones | | --- | --- | --- | --- | | Cm7 | 1 ♭3 5 ♭7 | drops D | 4 | | C9 | 1 3 5 ♭7 9 | E♭ becomes E | 4 | | C7 | 1 3 5 ♭7 | E♭, D becomes E | 3 | | CmMaj7 | 1 ♭3 5 7 | B♭, D becomes B | 3 | | Cm7♭5 | 1 ♭3 ♭5 ♭7 | G, D becomes G♭ | 3 | | C7sus4 | 1 4 5 ♭7 | E♭, D becomes F | 3 | | Cm6 | 1 ♭3 5 6 | B♭, D becomes A | 3 | | Cadd9 | 1 3 5 9 | E♭, B♭ becomes E | 3 | | Cmaj9 | 1 3 5 7 9 | E♭, B♭ becomes E, B | 3 | ## Set theory - Absolute pitch classes: {0, 3, 7, 10, 2} - Relative pitch classes: [0, 3, 7, 10, 2] - Normal order: [7, 10, 0, 2, 3] - Prime form: (01358) - Forte number: not claimed for this cardinality - Interval vector: <122230> ## Frequencies (close root position) | Note | MIDI | Frequency | | --- | --- | --- | | C3 | 48 | 130.81 Hz | | E♭3 | 51 | 155.56 Hz | | G3 | 55 | 196.00 Hz | | B♭3 | 58 | 233.08 Hz | | D4 | 62 | 293.66 Hz | ## Questions and answers ### What notes are in Cm9? Cm9 contains C, E♭, G, B♭ and D. The formula is 1, ♭3, 5, ♭7, 9. ### How do you play Cm9 on piano? Play C, E♭, G, B♭ and D together. Right hand fingers 1, 2, 3, 4, 5; left hand 5, 4, 3, 2, 1. E♭ and B♭ are black keys; C, G and D are white. ### What are the inversions of Cm9? 5 positions: root position C E♭ G B♭ D, Cm9/E♭, Cm9/G, Cm9/B♭, Cm9/D. ### What is the difference between Cm9 and Cm7? Drops D. 4 of the notes are shared. ### What is an easy Cm9 for small hands? The close, second inversion voicing, G3 B♭3 C4 D4 E♭4, spans 8 semitones or about 110 mm. ### What are the frequencies of Cm9? From C3 at A440 in 12-TET: 130.81, 155.56, 196.00, 233.08, 293.66 Hz. ### What is the set class of Cm9? Prime form (01358), interval vector <122230>. ### How do I transpose Cm9 to another key? Keep the 1, ♭3, 5, ♭7, 9 formula on the new root. C♯m9 is C♯, E, G♯, B, D♯; D♭m9 is D♭, F♭, A♭, C♭, E♭. ## Provenance Every derived value above is computed by the piano.org theory kernel from the root, the quality and the stated parameters. Nothing is hand-entered per chord. Machine record: https://piano.org/api/knowledge/v1/entities/chord:minor-9th:c Last reviewed: 2026-08-12