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.

Transpose0 st

Number

0

Letter

C

Binary

100000000000

One MIDI realization

60

The 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. Load a playable example to hear one MIDI realization in the Code Sequencer.

number

Integer 0-11 representing pitch class

0
4
11

letter

Traditional letter notation with optional accidentals

C
F#
Bb

radian

Equal temperament circle (2π/12 per semitone)

0
2.618
5.236

fifthRadian

Circle of fifths spacing (2π/12 per fifth)

0
3.142
4.712

sphericalRadians

Position 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)

0,0
2.618,3.142
5.236,4.712

binary

12-bit binary representation

100000000000
000100000000

Choose Load beside a convertible example to open its live player. Some catalog formats describe analysis or a display label and have no note realization yet.

NoteOne concrete MIDI pitch with an octave. Its pitch class keeps the note name while discarding that register.PointA relative pitch position measured in semitone steps. Anchor it to a note to obtain an absolute pitch; keep it unanchored to compare transposed shapes.IntervalA signed semitone distance between two pitches. Moving both endpoints together preserves the interval.Pitch-class setA selection of the twelve pitch classes, independent of octave and order. It says which pitches are present without choosing a chord root or voicing.Pc Set CollectionAn unordered collection of unique pitch class sets Pc Set Sequence CollectionAn unordered, octave-free collection of pc-set progressions. The pitch-class abstraction of a note-set-sequence collection; its `groupOf` is pc-set-sequence.