Key signature may consist of one or more sharps combined with one or more flats (such as a signature containing both F and B). Key signatures of this kind can be found in the music of Béla Bartók, for example. The effect of a key signature continues throughout a piece or movement, unless explicitly cancelled by another key signature. For example, if a five-sharp key signature is placed at the beginning of a piece, every A in the piece in any octave will be played as A sharp, unless preceded by an accidental (for instance, the A in scale 2 illustrated –
E (musical note) in pieces where E is in the key signature, in order to represent a diatonic, rather than a chromatic semitone; writing an E with a following E is regarded as a chromatic alteration of one scale degree. E (musical note) E is the third note of the C major scale, and mi in fixed-do solfège. It has enharmonic equivalents of F♭ (which is by definition a diatonic semitone above E) and D, amongst others. When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of Middle E (E) is approximately 329.628 Hz.