structural / Symbolic
Pitch class
One of the twelve pitches from C to B, independent of octave. Transposition rotates its position around the chromatic circle.
Try it
Select and transpose a pitch class
A pitch class identifies one position among twelve, regardless of octave. Choose a dot or bit, then rotate it by semitones.
Number
0Letter
CBinary
100000000000One MIDI realization
60The MIDI note uses octave 4 only for playback. It is not part of the pitch-class value.
Written forms
Ways to write this concept
Each notation describes the same underlying object. Open an example to see it in every other notation, or load it to hear one MIDI realization in the Code Sequencer.
number
Open guideInteger 0-11 representing pitch class
letter
Open guideTraditional letter notation with optional accidentals
radian
Open guideEqual temperament circle (2π/12 per semitone)
fifthRadian
Open guideCircle of fifths spacing (2π/12 per fifth)
sphericalRadians
Open guidePosition on tonal sphere where azimuth (φ) is chromatic position (2π/12 per semitone) and elevation (θ) is circle of fifths position (2π/12 per fifth)
binary
Open guide12-bit binary representation