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