🎼 Twelve-Tone Calculator — User Guide
Twelve-Tone Calculator generates melodic sequences based on the twelve-tone
technique. You define a vector of 12 intervals (i1–i12) and a starting note;
the tool calculates the sequence, displays it as a score, and makes it available
for playback, transformations, and MIDI export.
🎵 Generation Parameters
- Start Note — The pitch class where the sequence begins (C–B).
The octave is assigned automatically: C–F♯ start in octave 4, G–B in octave 3.
- Interval Vector (i1–i12) — Twelve integer values (in semitones) that
define the subsequent melodic intervals. Positive = ascending, negative = descending.
The default is all 1s (chromatic ascent).
- Limit to 12 notes — If active, the generated sequence is truncated
to exactly 12 notes.
⏱ Rhythm
- sequence-constrained — Note durations change at the boundaries of serial cycles.
- length-constrained — Note durations change every N notes, with N chosen
randomly from {2, 3, 5, 6}.
- constant — Every note has the same duration (chosen via Note Length).
- free — Every note receives an independent random duration.
- Note Length — Available only when Rhythm = constant:
Whole (4 beats), Half (2), Quarter (1), Eighth (½), Sixteenth (¼).
🎹 Harmony
- Harmony — Adds a bass clef accompaniment (left hand).
- Classic — Each note of the melody is doubled at the lower octave.
- On the beat — Chords fall on strong beats.
- Off the beat — Chords fall on weak beats.
🔄 Pitch Transformations (Pitch-Class)
- T — Transposition — Shifts all pitches by the chosen number of semitones
(−11 to +11) using the dropdown menu.
- I — Inversion — Inverts every interval around the first note
(ascending ↔ descending).
- R — Retrograde — Reverses the order of all notes.
- RI — Retrograde-Inversion — Applies I first, then R; one of the four
classical serial transformations.
🥁 Rhythmic Transformations
- S+ — Forward shift: the duration pattern is cyclically advanced
by two positions.
- S− — Backward shift: the duration pattern is cyclically moved back
by two positions.
- I — Rhythmic Inversion — Durations are ranked, and each is replaced
by its complementary rank (long ↔ short).
- R — Rhythmic Retrograde — Reverses the sequence of durations, leaving
pitches unchanged.
▶️ Playback
- Play — Starts playback using an acoustic piano soundfont at the current BPM.
It also animates the Pitch-Class Circle.
- Stop — Immediately stops playback.
- BPM slider (top right) — Playback speed (60–240 BPM);
does not affect the exported MIDI file.
- Metronome — Adds a click track during playback.
Three sounds available: DAW (noise burst), Beep (sine wave), Wood block.
💾 MIDI
- Download MIDI — Saves the current sequence as
twelve_tone.mid
along with a twelve_tone.txt file containing all generation parameters.
- Import MIDI — Reloads a previously exported
.mid file
(optionally with its associated .txt file), restoring the sequence and settings.
🔵 Pitch-Class Circle
The animated circle (top left) displays the 12 pitch classes like a clock face.
During playback, active notes light up in gold, and arcs trace the melodic intervals
traversed. The first and last arcs are highlighted in white.
🔁 Reset
Resets all parameters to their default values, clears the score, and reloads the page.
ℹ️ Contextual Help
Hover your mouse (or use the Tab key) over any control to see a short description
in the info panel at the bottom of the page.