B (musical note)

B, also known as Si, Ti, or, in some European countries, H, is the seventh note and the twelfth semitone of the fixed-Do solfège. Its enharmonic equivalents are C♭ (C-flat) and A (A-double sharp).

${ \new Staff \with{ \magnifyStaff #3/2 } << \time 2/1 \override Score.TimeSignature #'stencil = ##f { \clef bass b1_B \clef treble b'_B } >> }$

When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of Middle B (B₄) is 493.883 Hz. See pitch (music) for a discussion of historical variations in frequency.

Designation by octave

Scientific designation	Helmholtz designation	Octave name	Frequency (Hz)
B₋₁	B͵͵͵ or ͵͵͵B or BBBB	Subsubcontra	15.434
B₀	B͵͵ or ͵͵B or BBB	Subcontra	30.868
B₁	B͵ or ͵B or BB	Contra	61.735
B₂	B	Great	123.471
B₃	b	Small	246.942
B₄	b′	One-lined	493.883
B₅	b′′	Two-lined	987.767
B₆	b′′′	Three-lined	1975.533
B₇	b′′′′	Four-lined	3951.066
B₈	b′′′′′	Five-lined	7902.133
B₉	b′′′′′′	Six-lined	15804.266
B₁₀	b′′′′′′′	Seven-lined	31608.531

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

Diatonic scales

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

Jazz melodic minor

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

Variation of meaning by geographical region

The referent of the musical note B varies by location. See Musical note § History of note names for a discussion on other differences in letter naming of the notes.

In the United States, Canada, Australia, the United Kingdom, the Republic of Ireland, and the Netherlands, as described above, B usually refers to the note a semitone below C, while B-flat refers to the note a whole tone below C.

However, in Germany, Central and Eastern Europe, and Scandinavia, the label B is sometimes used for what, above, is called B-flat, and the note a semitone below C is called H. This makes possible certain spellings which are otherwise impossible, such as the BACH motif and the DSCH motif (the latter of which also uses the "S" name for what in Anglophone would be E-flat).