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
Theoretical key G♯ major) may have to be notated completely differently. Theoretical key In music theory, a theoretical key or impossible key is a key whose key signature has at least one double-flat or double-sharp. Double-flats and double-sharps are often used as accidentals, but placing them in the key signature (in music that uses equal temperament) makes the music generally impractical to read. For example, the key of G major is a key of this type, because its corresponding key signature has an F (on its leading-tone). An equal-tempered scale of G major comprises the same pitches as the A major scale,