Ab Major Ninth Chord

Chord Tones: Ab Major Ninth Chord

Symbol: maj9, M9, △9 — Formula: 1-3-5-7-9

Degree	Note	Frequency (A=440, Equal)
1	Ab	415.305 Hz
3	C	261.626 Hz
5	Eb	311.127 Hz
7	G	391.995 Hz
9	Bb	466.164 Hz

Chord Notation

Notation Type	Symbol / Value
Lead Sheet Symbol	Abmaj9
All Common Symbols	maj9, M9, △9
Interval Formula	1-3-5-7-9
Harmonic Category	lush

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

Inversion	Notes (low to high)	Bass Note	Slash Notation
Root Position	Ab – C – Eb – G – Bb	Ab	Ab Major Ninth Chord
First Inversion	C – Eb – G – Bb – Ab	C	Ab Major Ninth Chord/C
Second Inversion	Eb – G – Bb – Ab – C	Eb	Ab Major Ninth Chord/Eb
Third Inversion	G – Bb – Ab – C – Eb	G	Ab Major Ninth Chord/G
Fourth Inversion	Bb – Ab – C – Eb – G	Bb	Ab Major Ninth Chord/Bb

Harmonic Function

The Ab major ninth chord commonly functions as the submediant (♭VI) in C minor or subdominant in E♭ major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.

The major ninth chord extends the major seventh with a ninth, creating a lush, sophisticated sound central to jazz and R&B. It conveys spaciousness, warmth, and harmonic richness.

Common Progressions

The Ab Major Ninth Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

Imaj9-IVmaj9
Imaj9-ii9

Songs Featuring the Major Ninth Chord

Well-known songs where the Ab Major Ninth Chord — or this chord type — plays a prominent role:

Nights in White Satin – Moody Blues
Clair de Lune – Debussy (adapted)
Once in a While – jazz standard

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Note	Equal Temp.	Pythagorean	Just Intonation
Ab	415.305 Hz	417.657 Hz	418.601 Hz
C	261.626 Hz	260.740 Hz	261.626 Hz
Eb	311.127 Hz	309.026 Hz	313.951 Hz
G	391.995 Hz	391.111 Hz	392.438 Hz
Bb	466.164 Hz	463.538 Hz	470.926 Hz

Scales Containing the Ab Major Ninth Chord

These scales include the Ab Major Ninth Chord as a diatonic or characteristic chord:

Ab major Ab lydian Major Ninth Chord in all roots