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
Key signature be changed at any time in a piece, usually at the beginning of a measure, simply by notating the new signature, although if the new signature has no sharps or flats, a signature of naturals, as shown, is needed to cancel the preceding signature. If a change in signature occurs at the start of a new line on the page, where a signature would normally appear anyway, the new signature is customarily repeated at the end of the previous line to make the change more conspicuous. In traditional use, when the key signature change goes from sharps to flats or