B♭ (musical note)
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B♭ (B-flat; also called si bémol) is the eleventh step of the Western chromatic scale (starting from C).
It lies a diatonic semitone above A and a chromatic semitone below B, thus being enharmonic to A♯ although in some musical tunings, B♭ will have a different sounding pitch than A♯. B-flat is also enharmonic to C
.
When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the B♭ above middle C is approximately 466.164 Hz. See pitch (music) for a discussion of historical variations in frequency.
While orchestras tune to an A provided by the oboist, wind ensembles usually tune to a B-flat provided by a tuba, horn, or clarinet.
In Germany, Russia, Poland and Scandinavia this pitch is designated B, with 'H' used to designate the B-natural (or enharmonically C♭). Since the 1990s, B flat is often denoted Bb or "Bess" instead of B in Swedish music textbooks. Natural B is called B by Swedish jazz and pop musicians, but still denoted H in classical music. See B (musical note) for an explanation.
Designation by octave
| Scientific designation | Helmholtz designation | Bilinear music notation | Octave name | Frequency (Hz) |
|---|---|---|---|---|
| B♭-1 | B♭͵͵͵ or ͵͵͵B♭ or BBBB♭ | (-uB♭) | Subsubcontra | 14.568 |
| B♭0 | B♭͵͵ or ͵͵B♭ or BBB♭ | (-vB♭) | Subcontra | 29.135 |
| B♭1 | B♭͵ or ͵B♭ or BB♭ | (-wB♭) | Contra | 58.270 |
| B♭2 | B♭ | (-xB♭) | Great | 116.541 |
| B♭3 | b♭ | (-yB♭) | Small | 233.082 |
| B♭4 | b♭′ | (zB♭) | One-lined | 466.164 |
| B♭5 | b♭′′ | (yB♭) | Two-lined | 932.328 |
| B♭6 | b♭′′′ | (xB♭) | Three-lined | 1864.655 |
| B♭7 | b♭′′′′ | (wB♭) | Four-lined | 3729.310 |
| B♭8 | b♭′′′′′ | (vB♭}) | Five-lined | 7458.620 |
| B♭9 | b♭′′′′′′ | (uB♭) | Six-lined | 14917.240 |
| B♭10 | b♭′′′′′′′ | (tB♭) | Seven-lined | 29834.481 |
Scales
Common scales beginning on B♭
- B♭ Major: B♭ C D E♭ F G A B♭
- B♭ Natural Minor: B♭ C D♭ E♭ F G♭ A♭ B♭
- B♭ Harmonic Minor: B♭ C D♭ E♭ F G♭ A B♭
- B♭ Melodic Minor Ascending: B♭ C D♭ E♭ F G A B♭
- B♭ Melodic Minor Descending: B♭ A♭ G♭ F E♭ D♭ C B♭
- B♭ Ionian: B♭ C D E♭ F G A B♭
- B♭ Dorian: B♭ C D♭ E♭ F G A♭ B♭
- B♭ Phrygian: B♭ C♭ D♭ E♭ F G♭ A♭ B♭
- B♭ Lydian: B♭ C D E F G A B♭
- B♭ Mixolydian: B♭ C D E♭ F G A♭ B♭
- B♭ Aeolian: B♭ C D♭ E♭ F G♭ A♭ B♭
- B♭ Locrian: B♭ C♭ D♭ E♭ F♭ G♭ A♭ B♭
- B♭ Ascending Melodic Minor: B♭ C D♭ E♭ F G A B♭
- B♭ Dorian ♭2: B♭ C♭ D♭ E♭ F G A♭ B♭
- B♭ Lydian Augmented: B♭ C D E F♯ G A B♭
- B♭ Lydian Dominant: B♭ C D E F G A♭ B♭
- B♭ Mixolydian ♭6: B♭ C D E♭ F G♭ A♭ B♭
- B♭ Locrian ♮2: B♭ C D♭ E♭ F♭ G♭ A♭ B♭
- B♭ Altered: B♭ C♭ D♭ E
F♭ G♭ A♭ B♭