K-random — User Guide
K-random is a generative composition tool that produces short melodic sequences
using controlled randomness over pitch-class sets. Each sequence is delivered as audio (playback)
and as standard music notation, and can be exported as a MIDI file.
🎵 Generation Parameters
- Start Note — The pitch-class on which the sequence begins (C through B).
Octave is assigned automatically: C–F♯ start in octave 4, G–B in octave 3.
- K (number of notes) — How many notes the sequence contains (2–12).
With Repeated unchecked, K cannot exceed 12 (the full chromatic set).
- Repeated — When checked, the same pitch-class may appear more than once in the sequence.
When unchecked, each pitch-class is used at most once.
⏱ Rhythm
- Tempo mode
constant — Every note shares the same duration (chosen below).length-constrained — Duration changes every N notes, where N is drawn randomly from {2, 3, 5, 6}.free — Each note receives an independent random duration.
- Note Length — Available when Tempo = constant. Sets the shared duration:
Whole (4 beats), Half (2), Quarter (1), Eighth (½), Sixteenth (¼).
- Allow Triplets / Triplet probability — When enabled, notes may be grouped
as triplets with the probability set by the slider (0–100 %).
🎹 Instrument & Playback
- Instrument — Choose between Piano and Sax B♭ soundfonts for in-browser playback.
- BPM slider (top right) — Controls playback speed (60–240 BPM). Does not alter the MIDI file.
- Play / Pause / Stop — Standard transport controls. Pause freezes playback; press again (Continue) to resume.
- Loop — When checked, playback restarts automatically at the end of the sequence.
- Metronome — Adds a click track during playback. Three click sounds: DAW (noise burst), Beep (sine tone), Wood block.
🔄 Pitch-Class Transformations
Applied to the current sequence after generation. Each operation contacts the server and re-renders the notation.
- T — Transpose — Shifts all pitches by the chosen number of semitones (−12 to +12).
- I — Inversion — Reflects each interval around the first pitch (rising becomes falling).
- R — Retrograde — Reverses the order of pitches.
- RI — Retrograde-Inversion — Applies I then R; one of the four classical serial operations.
🥁 Rhythmic Transformations
- S+ — Shift forward — Cyclically advances the duration pattern by two positions.
- S− — Shift backward — Cyclically retards the duration pattern by two positions.
- I — Rhythmic Inversion — Ranks durations and swaps each with its complementary rank (long ↔ short).
- R — Rhythmic Retrograde — Reverses the sequence of durations while keeping pitches unchanged.
💾 MIDI
- Download MIDI — Saves the current sequence as a standard
.mid file,
ready to import into any DAW or notation software.
- Import MIDI — Loads an external MIDI file into the tool, making all
transformations available. The sequence type and tempo of the file should match the current settings, but
a
.txt file containing the proper settings can also be loaded. For compatibility reasons a GeCo-Tool
exported .txt file alone can also be imported (for example, scales 🎹)
🔵 Pitch-Class Circle
The animated circle (top left) visualises the chromatic scale as a clock-face. During playback,
active notes light up in gold and arcs trace the melodic intervals traversed. The first arc
(sequence start) and the last arc are highlighted in white.
📐 Generated Intervals
After generation, a row of coloured boxes shows the signed semitone interval between each
consecutive pair of notes (+n = ascending, −n = descending).
🔁 Reset
Restores all parameters to their defaults and clears the score. The page reloads completely.
ℹ️ Contextual Help
Hover over (or tab-focus) any control to see a short description in the help strip
at the bottom of the panel.
