A♭9: G♯/A♭ Dominant 9th Piano Chord

Scale degree, note, and interval measured from the root.
Degree	Note	Interval from root	Semitones
1	A♭	Perfect unison	0
3	C	Major third	4
5	E♭	Perfect fifth	7
♭7	G♭	Minor seventh	10
9	B♭	Major ninth	14

Construction

A♭ Dominant 9th = Root + Major 3rd + Perfect 5th + Minor 7th + Major 2nd = A♭, C, E♭, G♭, B♭

Note	Interval	Degree
A♭	Root	1
C	Major 3rd	3
E♭	Perfect 5th	5
G♭	Minor 7th	♭7
B♭	Major 2nd	9

Fingering

Note	Key color	Right hand	Left hand
A♭	black	thumb (1)	little finger (5)
C	white	index finger (2)	ring finger (4)
E♭	black	middle finger (3)	middle finger (3)
G♭	black	ring finger (4)	index finger (2)
B♭	black	little finger (5)	thumb (1)

Right hand: thumb (1) on A♭, index finger (2) on C, middle finger (3) on E♭, ring finger (4) on G♭, little finger (5) on B♭.

Left hand: little finger (5) on A♭, ring finger (4) on C, middle finger (3) on E♭, index finger (2) on G♭, thumb (1) on B♭.

Key Signature

A dominant chord points home to the key a fifth below its root: the A♭ Dominant 9th is the V (dominant) of D♭ Major, so the relevant key signature is that key's — 5 flats (B♭, E♭, A♭, D♭, G♭). Spelled as a scale, these notes are Ab Mixolydian.

B♭E♭A♭D♭G♭

Order of flats

Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.

B♭E♭A♭D♭G♭C♭F♭

Mnemonic: Battle Ends And Down Goes Charles’ Father

Chords in the Key of A♭ Major

These are the triads built on each degree of A♭ Major:

I — A♭ Major (major)

Degree	Numeral	Chord	Quality
1	I	A♭ Major	Major
2	ii	B♭ Minor	Minor
3	iii	C Minor	Minor
4	IV	D♭ Major	Major
5	V	E♭ Major	Major
6	vi	F Minor	Minor
7	vii°	G Diminished	Diminished

Scales That Include the A♭ Dominant 9th

A♭ Dominant 9th : Frequently Asked Questions

What is the A♭ Dominant 9th chord on piano?

The A♭ Dominant 9th chord contains the notes A♭ – C – E♭ – G♭ – B♭. On piano, play these notes together to sound the chord.

What notes are in the Ab Dominant 9th chord?

The Ab Dominant 9th chord (Ab9) contains 5 notes: Ab, C, Eb, Gb, Bb. Formula: R-M3-P5-m7-M9.

How is Ab9 used in music?

Ab9 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.

What is the scale degree formula for Ab9?

Ab9 uses scale degrees 1-3-5-b7-9, giving it its distinctive sound.

A♭ Dominant 9th in detail

Exact

Every pitch class is present and nothing outside the chord is added.

Type	Notes	Semitones	Span	Omissions and additions	Set relation
Close, root position	A♭3 C4 E♭4 G♭4 B♭4	14	193 mm	none	identical
Close, first inversion	C4 E♭4 G♭4 A♭4 B♭4	10	138 mm	none	identical
Close, second inversion	E♭4 G♭4 A♭4 B♭4 C5	9	124 mm	none	identical
Close, third inversion	G♭4 A♭4 B♭4 C5 E♭5	9	124 mm	none	identical
Close, fourth inversion	B♭3 C4 E♭4 G♭4 A♭4	10	138 mm	none	identical
Drop 2	G♭3 A♭3 C4 E♭4 B♭4	16	220 mm	none	identical
Drop 3	E♭3 A♭3 C4 G♭4 B♭4	19	261 mm	none	identical
Drop 2 and 4	C3 G♭3 A♭3 E♭4 B♭4	22	303 mm	none	identical

Reduced

A subset of the pitch classes: the identity is incomplete rather than altered.

Type	Notes	Semitones	Span	Omissions and additions	Set relation
Shell, root 9 3	A♭2 B♭3 C4	16	220 mm	omits E♭	subset
Guide tones, 3 and 9	C4 B♭4	10	138 mm	omits A♭ and E♭	subset
Rootless close	C4 E♭4 G♭4 B♭4	10	138 mm	omits A♭	subset

Spans are measured centre to centre at a 165 mm octave (standard keyboard geometry).

Position	Bass note	Notes in order	Figured bass	Semitones	Span
Root position	A♭	A♭3, C4, E♭4, G♭4, B♭4	9	14	193 mm
First inversion: A♭9/C	C	C4, E♭4, G♭4, A♭4, B♭4	7/6/5	10	138 mm
Second inversion: A♭9/E♭	E♭	E♭4, G♭4, A♭4, B♭4, C5	7/4/3	9	124 mm
Third inversion: A♭9/G♭	G♭	G♭4, A♭4, B♭4, C5, E♭5	7/4/2	9	124 mm
Fourth inversion: A♭9/B♭	B♭	B♭3, C4, E♭4, G♭4, A♭4	9/7/5	10	138 mm

One position per chord tone in the bass. Spans are for close position: voiced inversions appear under Voicings.

Change one note

Chords a single note away, and what moving that note does.

Chord	Change	Formula	Common tones
A♭7	drops B♭	1 3 5 ♭7	4
A♭add9	drops G♭	1 3 5 9	4
A♭maj9	G♭ becomes G	1 3 5 7 9	4
A♭m9	C becomes C♭	1 ♭3 5 ♭7 9	4
A♭maj7	G♭, B♭ becomes G	1 3 5 7	3
A♭m7	C, B♭ becomes C♭	1 ♭3 5 ♭7	3
A♭aug7	E♭, B♭ becomes E	1 3 ♯5 ♭7	3
A♭7sus4	C, B♭ becomes D♭	1 4 5 ♭7	3
A♭6	G♭, B♭ becomes F	1 3 5 6	3

Frequencies

Note	MIDI	Frequency
A♭3	56	207.65 Hz
C4	60	261.63 Hz
E♭4	63	311.13 Hz
G♭4	66	369.99 Hz
B♭4	70	466.16 Hz

Reference pitch A440, 12-TET, close root position.

Set theory: prime form, Forte number, interval vector

Absolute pitch class set: {8, 0, 3, 6, 10}
Normal order: [6, 8, 10, 0, 3]
Prime form: (02469)
Forte number: 5-34
Interval vector: <032221>

Pair	Interval	Semitones	Interval class
A♭ to C	Major third	4	4
A♭ to E♭	Perfect fifth	7	5
A♭ to G♭	Minor seventh	10	2
A♭ to B♭	Major ninth	14	2
C to E♭	Minor third	3	3
C to G♭	Tritone	6	6
C to B♭	Minor seventh	10	2
E♭ to G♭	Minor third	3	3
E♭ to B♭	Perfect fifth	7	5
G♭ to B♭	Major third	4	4

Where these facts come from

Every value on this page is derived from the note formula for a dominant 9th applied to the root A♭, using standard music theory. Nothing here is hand-entered per chord, so the notes, intervals, inversions and frequencies cannot drift out of agreement with each other. Pitches assume 12-TET at A440.

A♭ Dominant 9th

Fingerings

A♭ Dominant 9th: notes and degrees