A b (musical note)

A♭ (musical note)

A♭ (A-flat; also called la bémol) is the ninth semitone of the solfège.

It lies a diatonic semitone above Gand a chromatic semitone below A, thus being enharmonic to G♯, even though in some musical tunings, A♭ will have a different sounding pitch than G♯.

When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the A♭ above middle C (or A♭₄) is approximately 415.305 Hz. See pitch (music) for a discussion of historical variations in frequency.

A♭/G♯ is the only note to have only one other enharmonic.

Designation by octave

Scientificdesignation	Helmholtzdesignation	Octave name	Frequency (Hz)
A♭−1	A♭͵͵͵ or ͵͵͵A♭ or AAAA♭	Octocontra	12.978
A♭0	A♭͵͵ or ͵͵A♭ or AAA♭	Subcontra	25.957
A♭1	A♭͵ or ͵A♭ or AA♭	Contra	51.913
A♭2	A♭	Great	103.826
A♭3	a♭	Small	207.652
A♭4	a♭′	One-lined	415.305
A♭5	a♭′′	Two-lined	830.609
A♭6	a♭′′′	Three-lined	1661.219
A♭7	a♭′′′′	Four-lined	3322.438
A♭8	a♭′′′′′	Five-lined	6644.875
A♭9	a♭′′′′′′	Six-lined	13289.750
A♭10	a♭′′′′′′′	Seven-lined	26579.501

Scales

Common scales beginning on A♭

• A♭ Major: A♭ B♭ C D♭ E♭ F G A♭
• A♭ Natural Minor: A♭ B♭ C♭D♭ E♭ F♭ G♭ A♭
• A♭ Harmonic Minor: A♭ B♭C♭ D♭ E♭ F♭ G A♭
• A♭ Melodic Minor Ascending: A♭ B♭ C♭ D♭ E♭ F G A♭
• A♭ Melodic Minor Descending: A♭ G♭ F♭ E♭ D♭ C♭ B♭A♭

Diatonic scales

• A♭ Ionian: A♭ B♭ C D♭ E♭F G A♭
• A♭ Dorian: A♭ B♭ C♭ D♭E♭ F G♭ A♭
• A♭ Phrygian: A♭ B  C♭ D♭E♭ F♭ G♭ A♭
• A♭ Lydian: A♭ B♭ C D E♭ F G A♭
• A♭ Mixolydian: A♭ B♭ C D♭E♭ F G♭ A♭
• A♭ Aeolian: A♭ B♭ C♭ D♭E♭ F♭ G♭ A♭
• A♭ Locrian: A♭ B  C♭ D♭ E F♭ G♭ A♭

Jazz melodic minor

• A♭ Ascending Melodic Minor: A♭ B♭ C♭ D♭ E♭ F G A♭
• A♭ Dorian ♭2: A♭ B  C♭D♭ E♭ F G♭ A♭
• A♭ Lydian Augmented: A♭ B♭C D E F G A♭
• A♭ Lydian Dominant: A♭ B♭ C D E♭ F G♭ A♭
• A♭ Mixolydian ♭6: A♭ B♭ C D♭ E♭ F♭ G♭ A♭
• A♭ Locrian ♮2: A♭ B♭ C♭D♭ E  F♭ G♭ A♭
• A♭ Altered: A♭ B  C♭ D  E F♭ G♭ A♭