Pitch class: Difference between revisions
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A ''pitch class'' is a set (equivalence class) of all pitches that are a whole number of octaves apart, e.g., the pitch class C consists of the Cs in all octaves. Thus the pitch class "C" is the set | A ''pitch class'' is a set (equivalence class) of all pitches that are a whole number of octaves (2/1) apart, e.g., the pitch class C consists of the Cs in all octaves. Thus the pitch class "C" is the set | ||
<math>{..., C_{-2}, C_{-1}, C_0, C_1, C_2 ...}</math> | <math>{..., C_{-2}, C_{-1}, C_0, C_1, C_2 ...}</math> | ||
In terms of frequencies expressed in hertz, assuming a base frequency for middle C of 262 Hz, this would be {... 65.5, 131, 262, 524, 1028 ...}. In terms of midi note numbers, we can write it as {... 36, 48, 60, 72, 84 ...}. | In terms of frequencies expressed in hertz, assuming a base frequency for middle C of 262 Hz, this would be {... 65.5, 131, 262, 524, 1028 ...}. In terms of midi note numbers, we can write it as {... 36, 48, 60, 72, 84 ...}. | ||
In a [[nonoctave]] xenharmonic system, an interval other than the octave might be used to define equivalence. For example, in [[Bohlen-Pierce]] tuning, all pitches separated by a whole number of tritaves (3/1) may be considered equivalent. | |||
=Links= | =Links= | ||
http://en.wikipedia.org/wiki/Pitch_class | |||
[[Category:pitch]] | |||
[[Category:theory]] | [[Category:theory]] | ||
[[Category:tone]] | [[Category:tone]] | ||