Pitch class information

${ \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \key c \major \time 4/4 <c c'>1 } }$

Perfect octave

${ \override Score.TimeSignature #'stencil = ##f \new PianoStaff << \new Staff \relative c' { \clef treble \key c \major \time 4/4 <c' c' c'>1 \bar "|." } \new Staff \relative c' { \clef bass \key c \major \time 4/4 <c c, c, c,>1 } >> }$

All Cs from C₁ to C₇ inclusive

In music, a pitch class (p.c. or pc) is a set of all pitches that are a whole number of octaves apart; for example, the pitch class C consists of the Cs in all octaves. "The pitch class C stands for all possible Cs, in whatever octave position."^[1] Important to musical set theory, a pitch class is "all pitches related to each other by octave, enharmonic equivalence, or both."^[2] Thus, using scientific pitch notation, the pitch class "C" is the set

{C_n : n is an integer} = {..., C₋₂, C₋₁, C₀, C₁, C₂, C₃ ...}.

Although there is no formal upper or lower limit to this sequence, only a few of these pitches are audible to humans. Pitch class is important because human pitch-perception is periodic: pitches belonging to the same pitch class are perceived as having a similar quality or color, a property called "octave equivalence".

Psychologists refer to the quality of a pitch as its "chroma".^[3] A chroma is an attribute of pitches (as opposed to tone height), just like hue is an attribute of color. A pitch class is a set of all pitches that share the same chroma, just like "the set of all white things" is the collection of all white objects.^[4]

In standard Western equal temperament, distinct spellings can refer to the same sounding object: B♯₃, C₄, and D₄ all refer to the same pitch, hence share the same chroma, and therefore belong to the same pitch class. This phenomenon is called enharmonic equivalence.

^ Arnold Whittall, The Cambridge Introduction to Serialism (New York: Cambridge University Press, 2008): 276. ISBN 978-0-521-68200-8 (pbk).
^ Don Michael Randel, ed. (2003). "Set theory", The Harvard Dictionary of Music, p.776. Harvard. ISBN 9780674011632.
^ Tymoczko, Dmitri (2011). A Geometry of Music: Harmony and Counterpoint in the Extended Common Practice, p.30. Oxford Studies in Music Theory. ISBN 9780199714353.
^ Müller, Meinard (2007). Information Retrieval for Music and Motion, p.60. ISBN 9783540740483. "A pitch class is defined to be the set of all pitches that share the same chroma."

[1] Arnold Whittall, The Cambridge Introduction to Serialism (New York: Cambridge University Press, 2008): 276. ISBN 978-0-521-68200-8 (pbk).

[2] Don Michael Randel, ed. (2003). "Set theory", The Harvard Dictionary of Music, p.776. Harvard. ISBN 9780674011632.

[3] Tymoczko, Dmitri (2011). A Geometry of Music: Harmony and Counterpoint in the Extended Common Practice, p.30. Oxford Studies in Music Theory. ISBN 9780199714353.

[4] Müller, Meinard (2007). Information Retrieval for Music and Motion, p.60. ISBN 9783540740483. "A pitch class is defined to be the set of all pitches that share the same chroma."

Pitch class information

and 19 Related for: Pitch class information

Pitch class

Pitch interval

Pitch

Absolute pitch

Musical note

Pitch class space

Circle of fifths

Interval class

List of set classes

Octave

Cricket pitch

Harmonic pitch class profiles

Hicaz pitch class set

Pitch space

Interval vector

List of pitch intervals

Rast pitch class set

Forte number

Modulatory space