Musical notation its "natural" form, which means that any sharps or flats applying to that note from the key signature or from accidentals are cancelled. Sometimes a courtesy accidental is used in music where it is not technically required, to remind the musician of what pitch the key signature requires. Following the key signature is the time signature. The time signature typically consists of two numbers, with one of the most common being "4/4". The top "4" indicates that there are four beats per measure (also called bar). The bottom "4" indicates that each of those beats are quarter notes. Measures divide
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