It provides an unambiguous means of identifying a note in terms of textual notation rather than frequency, while at the same time avoiding the transposition conventions that are used in writing the music for instruments such as the clarinet and guitar. Scientific pitch notation is often used to specify the range of an instrument. "C 4" and all of its possible variants (C, C ♭, C, C ♯, C ) would properly be designated as being in octave "4"."B 3" and all of its possible variants (B, B ♭, B, B ♯, B ) would properly be designated as being in octave "3".The octave number is tied to the alphabetic character used to describe the pitch, with the division between note letters ‘B’ and ‘C’, thus: For example, C 4 is one note above B 3, and A 5 is one note above G 5. Thus, A 0 refers to the first A above C 0 and middle C (the one-line octave's C or simply c′) is denoted as C 4 in SPN. The octave number increases by 1 upon an ascension from B to C. Octave 0 of SPN marks the low end of what humans can actually perceive, with the average person being able to hear frequencies no lower than 20 Hz as pitches. The octave 0 of the scientific pitch notation is traditionally called the sub-contra octave, and the tone marked C 0 in SPN is written as ,C or C, or CCC in traditional systems, such as Helmholtz notation. The notation makes use of the traditional tone names (A to G) which are followed by numbers showing which octave they are part of.įor standard A440 pitch equal temperament, the system begins at a frequency of 16.35160 Hz, which is assigned the value C 0. 5 Scientific pitch versus scientific pitch notation.