A Minor 9th Chord: Notes, Voicings, and How to Play It

The cheapest complete voicing of this chord on a guitar puts its ninth a semitone below its third. Two fingers at the 5th fret on the fourth and third strings, three strings left open, x 0 5 5 0 0, and the open B lands directly under the C. Every guide to voicing extensions says to keep the 9th clear of the ♭3. This shape does the opposite, costs almost nothing, and the rub is most of why players reach for it.

Try It: Am9 in the Chord Finder

Sound Am7, then add a B and move it above and below the C in turn. It is the same chord and two different sounds.

The Notes of Am9

Written out: A, C, E, G, B. Five notes and no accidentals. Laid out as a scale they read A, B, C, E, G, which shows where the chord keeps its edge: B to C is the one semitone in it, and every awkward voicing on this page is that pair in a different place.

How Am9 Is Built

Am7 is A, C, E and G, and a B goes on top. The 9th is a natural tension over a minor seventh, ticked rather than crossed in the grid in the guide to extended chords, so nothing here needs permission.

What the B changes is that the chord now has something to get wrong. Am7 contains no interval narrower than a minor 3rd, which is why it sounds restful. The B is the first note in the stack that has to be placed: a major 7th above the C it vanishes into the chord, a semitone below it and it is the loudest thing in the room. Both are Am9.

Sharpen the C to C♯ and the chord becomes A9, with a tritone and a destination. Leave the G out and A, C, E and B is Am add9, with no seventh holding the ninth up.

Everything Above the Root Is Cmaj7

C, E, G and B is a C major 7th in root position, so Am9 is that chord with an A underneath it. In the key of C, the tonic seventh and the submediant ninth therefore differ by one bass note and nothing else.

Am9 on the Piano

A to B is fourteen semitones, so one hand cannot hold the chord in root position. A2 goes to the left and C4, E4, G4 and B4 to the right, a major 7th across under 1, 2, 3 and 5. That right hand is a Cmaj7 grip, which most pianists own before they ever see this chord symbol.

The only decision that matters up there is where the B goes. Above the C it reads as air. Below it, as in A2, B3, C4, E4 and G4, the chord takes on the crunch of the open guitar shape. Neither is wrong and they are not interchangeable, so choose.

Keep the left hand thin down there. A and E is safe; A and C is a minor 3rd below the bass clef, which turns to mud for the reasons the pillar’s section on low register spacing sets out. Spread as A2, E3, G3, C4 and B4, the chord has nothing closer than a minor 3rd anywhere in it.

Am9 on the Guitar

Take the open shape apart and the semitone explains itself. Above the bass, x 0 5 5 0 0 sounds G3, B3, C4 and E4, that Cmaj7 lying in its third inversion, seventh underneath root. The A2 beneath turns it into Am9, and the B is under the C only because of how the Cmaj7 happened to be rotated.

Rotate it the other way and the crunch goes. Open Cmaj7 is x 3 2 0 0 0. Add the sixth string at the 5th fret for a low A and 5 3 2 0 0 0 is Am9 across all six strings, A2, C3, E3, G3, B3, E4, the B now a major 7th above the C. The price is a three fret reach on the thickest strings, little finger at the 5th, ring at the 3rd, middle at the 2nd.

The barre version is the Am7 shape with one note changed. Am7 at the 5th fret is 5 7 5 5 5 5, and the top string there sounds an A, a third copy of the root. Move it to the 7th fret and 5 7 5 5 5 7 is Am9: the ninth arrives and all that was spent is a duplicate.

The same voicing on the neighbouring root shows how much of this is luck. Em9 at the nut is 0 x 0 0 0 2, four open strings and one finger; on A it is that shape barred at the 5th fret, 5 x 5 5 5 7, index flattened across five strings with the little finger two frets ahead. Nothing about the chord got harder, the notes simply moved off the open strings.

Inversions

Hardly any of these keep the name. With C in the bass the five notes are a C major 7th with an added 6th, and a chart will say so. With E lowest they read as an E minor chord with an 11th and a flattened 13th.

Two rotations are warnings. Put the G at the bottom and the C above it sits a semitone over the B, which is the natural 11th against a major 3rd, the most reliable way there is to make a chord sound broken. Put the B at the bottom and the C becomes a flattened 9th over the bass, which is worse.

Voicings

Which Keys Contain Am9

• degree 6 (VI) of C major
• degree 2 (II) of G major
• degree 1 (I) of A natural minor
• degree 1 (I) of A dorian
• degree 4 (IV) of E natural minor
• degree 4 (IV) of E harmonic minor

The B settles half a question. A minor seventh on this root sits equally well in A natural minor, A dorian and A phrygian and says nothing about which. Am9 rules phrygian out, since that mode’s second degree is B♭ and this chord insists on B natural. The 6th it still declines to decide, F or F♯, so natural minor and dorian both survive and a soloist keeps that choice bar by bar.

The two entries on E are a pair with one absentee. As the iv chord of E minor this chord survives the harmonic form, D♯ not being in it, but not the melodic form, which raises C to C♯ and takes the ♭3 away.

Where Am9 Shows Up

The first row is a bass move dressed as a chord change. Cmaj7 and Am9 share C, E, G and B, so a keyboard pad holds still while the bass walks down to A and the harmony changes name without a voice moving. It also means the vi chord in C carries the key’s leading note inside it: B is a 9th here and the note that most wants to resolve there. Sitting on Am9 keeps that pull alive under a surface doing nothing, which is a fair description of what neo soul does with the chord.

G major puts the same B to opposite use. As the ii it is not a leading note but the third of the tonic triad, waiting two chords ahead. A melody landing on B over Am9 holds it as the 13th of the D7 and arrives on it again as the third of the G, one note across three chords.

The E minor row hides the neatest fact about the chord. E, G and B is the tonic triad of that key and all three are inside Am9, so the i is contained whole in its own iv. Am7 cannot do this, having no B. Going from Em to Am9 adds an A and a C and takes nothing away, which on a guitar means the open E and B strings ring through the change untouched.

A dorian is where the chord gets to be the tonic rather than a colour, and the open shape at the top of this page is the sound meant. Barred, it sits at the 5th fret with Bm7 as the same grip two frets above.

Related Chords

• A Minor 7th Chord the four notes this is built on
• C Major 7th Chord the same chord without its bass note
• A Dominant 9th Chord the same B over a major 3rd
• A Minor 6th Chord the other extended minor sound on this root
• A Minor Chord the triad at the bottom of it
• Seventh Chords: The Complete Guide

Learn More

• Extended Chords: Which Tensions Work, and How to Voice Them
• Chord Inversions and Voice Leading
• Diatonic Chords: A Beginner’s Guide
• The Circle of Fifths Explained
• The A Dorian Scale