# A Minor 9th piano chord (Am9) Am9 contains A, C, E, G and B. A minor seventh with the ninth added on top. Every note is a white key. - Canonical page: https://piano.org/chords/minor-9th/a/ - Entity: chord:minor-9th:a - Notes: A C E G B - Formula: 1 ♭3 5 ♭7 9 - Intervals from root: P1, m3, P5, m7, M9 - Interval stack (semitones): 3 4 3 4 - Also written: Am9, Am9, A minor 9th - Parameters: A440, 12-TET, 165 mm octave, spans centre to centre ## Construction | Degree | Note | Interval from root | Semitones | | --- | --- | --- | --- | | 1 | A | Perfect unison | 0 | | ♭3 | C | Minor third | 3 | | 5 | E | Perfect fifth | 7 | | ♭7 | G | Minor seventh | 10 | | 9 | B | Major ninth | 14 | ## Fingering Rest your right hand over the notes with finger 1 on A, finger 2 on C, finger 3 on E, finger 4 on G, finger 5 on B. 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 | A | A3 C4 E4 G4 B4 | 9 | 14 st, 193 mm | | First inversion (Am9/C) | C | C4 E4 G4 A4 B4 | 7/6/5 | 11 st, 151 mm | | Second inversion (Am9/E) | E | E4 G4 A4 B4 C5 | 7/4/3 | 8 st, 110 mm | | Third inversion (Am9/G) | G | G4 A4 B4 C5 E5 | 7/4/2 | 9 st, 124 mm | | Fourth inversion (Am9/B) | B | B3 C4 E4 G4 A4 | 9/7/5 | 10 st, 138 mm | ## Voicings (11) | Voicing | Notes | Span | Relation | Omits or adds | | --- | --- | --- | --- | --- | | Close, root position | A3 C4 E4 G4 B4 | 14 st, 193 mm | identical | none | | Close, first inversion | C4 E4 G4 A4 B4 | 11 st, 151 mm | identical | none | | Close, second inversion | E4 G4 A4 B4 C5 | 8 st, 110 mm | identical | none | | Close, third inversion | G4 A4 B4 C5 E5 | 9 st, 124 mm | identical | none | | Close, fourth inversion | B3 C4 E4 G4 A4 | 10 st, 138 mm | identical | none | | Drop 2 | G3 A3 C4 E4 B4 | 16 st, 220 mm | identical | none | | Drop 3 | E3 A3 C4 G4 B4 | 19 st, 261 mm | identical | none | | Drop 2 and 4 | C3 G3 A3 E4 B4 | 23 st, 316 mm | identical | none | | Shell, root 9 ♭3 | A2 B3 C4 | 15 st, 206 mm | subset | omits E | | Guide tones, ♭3 and 9 | C4 B4 | 11 st, 151 mm | subset | omits A and E | | Rootless close | C4 E4 G4 B4 | 11 st, 151 mm | subset | omits A | ## One-edit neighbors | Becomes | Edit | Changes | Common tones | | --- | --- | --- | --- | | Am7 | 1 ♭3 5 ♭7 | drops B | 4 | | A9 | 1 3 5 ♭7 9 | C becomes C♯ | 4 | | A7 | 1 3 5 ♭7 | C, B becomes C♯ | 3 | | AmMaj7 | 1 ♭3 5 7 | G, B becomes G♯ | 3 | | Am7♭5 | 1 ♭3 ♭5 ♭7 | E, B becomes E♭ | 3 | | A7sus4 | 1 4 5 ♭7 | C, B becomes D | 3 | | Am6 | 1 ♭3 5 6 | G, B becomes F♯ | 3 | | Aadd9 | 1 3 5 9 | C, G becomes C♯ | 3 | | Amaj9 | 1 3 5 7 9 | C, G becomes C♯, G♯ | 3 | ## Set theory - Absolute pitch classes: {9, 0, 4, 7, 11} - Relative pitch classes: [0, 3, 7, 10, 2] - Normal order: [4, 7, 9, 11, 0] - Prime form: (01358) - Forte number: not claimed for this cardinality - Interval vector: <122230> ## Frequencies (close root position) | Note | MIDI | Frequency | | --- | --- | --- | | A3 | 57 | 220.00 Hz | | C4 | 60 | 261.63 Hz | | E4 | 64 | 329.63 Hz | | G4 | 67 | 392.00 Hz | | B4 | 71 | 493.88 Hz | ## Questions and answers ### What notes are in Am9? Am9 contains A, C, E, G and B. The formula is 1, ♭3, 5, ♭7, 9. ### How do you play Am9 on piano? Play A, C, E, G and B together. Right hand fingers 1, 2, 3, 4, 5; left hand 5, 4, 3, 2, 1. Every note is a white key. ### What are the inversions of Am9? 5 positions: root position A C E G B, Am9/C, Am9/E, Am9/G, Am9/B. ### What is the difference between Am9 and Am7? Drops B. 4 of the notes are shared. ### What is an easy Am9 for small hands? The close, second inversion voicing, E4 G4 A4 B4 C5, spans 8 semitones or about 110 mm. ### What are the frequencies of Am9? From A3 at A440 in 12-TET: 220.00, 261.63, 329.63, 392.00, 493.88 Hz. ### What is the set class of Am9? Prime form (01358), interval vector <122230>. ### How do I transpose Am9 to another key? Keep the 1, ♭3, 5, ♭7, 9 formula on the new root. Cm9 is C, E♭, G, B♭, D; C♯m9 is C♯, E, G♯, B, D♯. ## 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:a Last reviewed: 2026-08-12