structural / Symbolic

Pc Set Sequence

An ordered sequence of pitch class sets that may contain duplicates

Try it

Resolve a progression in a key

Roman numerals describe functions relative to a selected key. Change the key to reinterpret the same numerals, or transpose the resulting MIDI notes by a fixed number of semitones. These are different operations.

KeyRoman progression

Transpose0 st

Selected chord: Cmaj7 · octave-free set

Key

C major

Scale notes

C-D-E-F-G-A-B

Pitch classes

0-4-7-11

Resolved chord symbols (before shift)

Cmaj7 - G7 - Am7 - Fmaj7

C is the tonic; major supplies the scale. Roman numerals resolve to diatonic seventh chords where available. The semitone control moves the resolved notes after that interpretation.

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.

binary

Sequence of binary pc-set representations

100010111101-100010010101-100010111101

numbers

Sequence of pc-set number representations

0-4-7,5-9-0,0-4-7

timed

The same progression with durations committed — comma-separated pcSet:duration pairs (pitch classes 0–11, duration in beats). Timing is a notation of the one concept, not a separate concept.

0-4-7:2,5-9-0:2,7-11-2:4

roman

Roman numeral notation, when applicable

I-IV-V-I
ii-V-I

quality

Sequence of quality names, when applicable

maj-maj-maj
min-dom-maj

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.

Note Set SequenceAn ordered sequence of note sets (chords) that may contain duplicates Song formA chord progression arranged by labeled section (intro, verse, chorus, bridge…) — the harmonic skeleton of a lead sheet or guitar-chord chart. An ordered, named sequence whose sections are chord progressions (its `groupOf` is note-set-sequence). Forget the labels/order and it becomes a collection of progressions; forget pitch and it becomes a point-song-form (a key-independent structural shape for comparing songs).Point Set SequenceAn ordered sequence of point-sets that may contain duplicates Point song formA song form reduced to non-pitch-specific shapes — section labels and order are kept, but each chord is a point-set (offsets, no key). This is the transposition-invariant structural fingerprint of a song: two songs in different keys with the same form land on the same point-song-form, so it is the natural representation for song-to-song similarity. Its `groupOf` is point-set-sequence.Pitch-class sequenceAn ordered line of pitch classes without fixed octaves. Choose registers to turn it into MIDI notes.Pc scoreAn octave-free polyphonic texture — simultaneous pc-sequences (lines of pitch classes). The octaveless abstraction of a score; keeps voice independence and harmony but drops register. Its `groupOf` is pc-sequence.