Flat (music)

Flat (music)
In music, flat (Italian bemolle for "soft B") means "lower in pitch". Flat is the opposite of sharp, which is a raising of pitch. In musical notation, flat means "lower in pitch by one semitone (half step)", notated using the symbol which is derived from a stylised lowercase 'b'.
Example
Under twelve-tone equal temperament, D for instance is enharmonically equivalent to C, and G is equivalent to F. In any other tuning system, such enharmonic equivalences in general do not exist.
Key signature
Flats are used in the key signatures of
F major / D minor (B)
B major / G minor (adds E)
E major / C minor (adds A)
A major / F minor (adds D)
D major / B minor (adds G)
G major / E minor (adds C)
C major / A minor (adds F)
The order of flats in the key signatures of music notation, following the circle of fifths, is B, E, A, D, G, C and F (mnemonics for which include Battle Ends And Down Goes Charles' Father and Before Eating A Doughnut Get Coffee First).
Accidental
When used as an accidental, it is written to the left of the note head.When used as an accidental, flat is applied to the note following sharp within the measure. However, unlike the key signature, it does not apply to notes that have the same note name but a different octave.
However, if it is written as an accidental, all key signatures and other signs are ignored, and it is read based on the basic tone (natural tone).
To cancel the flat used as an accidental in the same octave within the same bar, use other accidentals such as a natural (♮).
Related symbols
A double flat also exists, which looks like (similar to two flats, ♭♭) and lowers a note by two semitones, or a whole step.
A quarter-tone flat, half flat, or demiflat indicating the use of quarter tones, may be marked with various symbols including a flat with a slash or a reversed flat sign. A three-quarter-tone flat, flat and a half or sesquiflat, is represented by a demiflat and a regular flat.
Although very uncommon, a triple flat can sometimes be found. It lowers a note three semitones, or a whole tone and a semitone.
And theoretically, the symbol of a quadruple flat or beyond could be also considered sometimes.
Unicode
The Unicode character ♭ (U+266D) can be found in the block Miscellaneous Symbols; its HTML entity is &#9837;. Other assigned flat signs are as follows:
Etc.
Historically, in order to raise a double flat to a flat, it would be denoted as ♮♭ or ♭♮ instead of ♭. In modern notation, the natural sign has been often omitted.
To allow extended just intonation, composer Ben Johnston uses a flat as an accidental to indicate a note is lowered 70.6 cents.
In intonation, flat can also mean "slightly lower in pitch" (by some unspecified amount). If two simultaneous notes are slightly out-of-tune, the lower-pitched one (assuming the higher one is properly pitched) is "flat" with respect to the other. Furthermore, the verb flatten means to lower the pitch of a note, typically by a small musical interval.
In environments where the symbol is not supported, or in text notation for specific reasons, a double flat is sometimes written as ♭♭, bb or etc. Likewise, a triple flat can also be written as ♭♭♭ or etc.
See also
Sharp (music)
Electronic tuner
References
External links
Musical notation
Pitch (music)