Editing Scientific pitch notation (section)

==Nomenclature==
The notation makes use of the traditional tone names (A to G) which are followed by numbers showing which [[octave]] they are part of.

For standard [[A440 (pitch standard)|A440]] pitch [[Equal temperament#Twelve-tone equal temperament|equal temperament]], the system begins at a frequency of 16.35160 [[Hertz|Hz]], which is assigned the value '''C<sub>0</sub>'''. 

The octave 0 of the scientific pitch notation is traditionally called the [[sub-contra octave]], and the tone marked C<sub>0</sub> in SPN is written as '',,C'' or ''C,,'' or ''CCC'' in traditional systems, such as [[Helmholtz notation]]. Octave 0 of SPN marks the low end of what humans can actually perceive, with the average person being able to [[Audio frequency|hear frequencies]] no lower than 20 Hz as pitches.

The octave number increases by 1 upon an ascension from B to C. Thus, ''A<sub>0</sub>'' refers to the first A ''above'' C<sub>0</sub> and [[middle C]] (the [[one-line octave]]'s C or simply {{nowrap|'''c′'''}})  is denoted as ''C<sub>4</sub>'' in SPN.  For example, C<sub>4</sub> is one note above B<sub>3</sub>, and A<sub>5</sub> is one note above G<sub>5</sub>.

The octave number is tied to the alphabetic character used to describe the pitch, with the division between note letters 'B' and 'C', thus:
:* "B<sub>3</sub>" and all of its possible variants (B{{music|bb}}, B{{music|b}}, B, B{{music|#}}, B{{music|x}}) would properly be designated as being in octave "3".
:* "C<sub>4</sub>" and all of its possible variants (C{{music|bb}}, C{{music|b}}, C, C{{music|#}}, C{{music|x}}) would properly be designated as being in octave "4".
:* In equal temperament "C{{music|b}}{{sub|4}}" is same frequency as "B{{sub|3}}".