Accidental (music) Accidental (music) In music, an accidental is a note of a pitch (or pitch class) that is not a member of the scale or mode indicated by the most recently applied key signature. In musical notation, the sharp (), flat (), and natural () symbols, among others, mark such notes—and those symbols are also called accidentals. In the measure (bar) where it appears, an accidental sign raises or lowers the immediately following note (and any repetition of it in the bar) from its normal pitch, overriding sharps or flats in the key signature. A note is usually raised or lowered
Scientific pitch notation frequencies, in other words, standard concert pitch and twelve-tone equal temperament). When a piano is tuned to just intonation, C refers to the same key on the keyboard, but a slightly different frequency. Mathematically, given the number formula_1 of semitones above middle C, the fundamental frequency in hertz is given by formula_2 (see twelfth root of two). Given the MIDI NoteOn number formula_3, the frequency of the note is normally formula_4 Hz, using standard tuning. Scientific pitch (q.v.) is an absolute pitch "standard", first proposed in 1713 by French physicist Joseph Sauveur. It was defined so that all Cs are