Key signature A minor as each accidental may be notated explicitly as required, or the piece may be modal or atonal. An example is Bartók's Piano Sonata, which has no fixed key and is highly chromatic. If not bound by common practice conventions, microtones can also be notated in a key signature; which microtonal symbols are used depends on the system. The common practice period conventions are so firmly established that some musical notation programs have been unable to show nonstandard key signatures until recently. The use of a one-flat signature developed in the Medieval period, but signatures with more than one
F (musical note) the key signature, in order to represent a diatonic, rather than a chromatic semitone; writing an F with a following F is regarded as a chromatic alteration of one scale degree (E and F do not sound the same, except in some tunings that define the notes in that way). F (musical note) F is a musical note, the fourth above C. It is also known as fa in fixed-do solfège. It has enharmonic equivalents of E and G, amongst others. When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of