Composition Showcase: Three-Layer Coil Editor

The Three-Layer Architecture

Prime Period Theory organises musical material across three distinct perceptual and structural strata. Rather than treating pitch, rhythm, and harmony as attributes of a single note stream, PPT separates them into independent layers that are mapped against each other at playback time. This mirrors the way the ear actually processes music — rhythm is a scaffold on which melodic events land, and harmonic colour is a field that envelops the melodic line.

Layers are displayed bottom-to-top in the editor — Rhythm at the bottom, Harmony above it, Melody at the top — reflecting the compositional dependency chain: rhythm provides time, harmony provides colour, melody provides line.

Uniform Solfège Input

Uniform Solfège (PPT's base-12 notation layer) names all twelve chromatic pitch classes relative to a tonic. Unlike traditional solfège, it is fully chromatic — every semitone step has a unique, unambiguous syllable name. The twelve syllables are:

To enter a phrase via keyboard, click a row to focus it, then type syllable names separated by spaces into the text input above and press Enter. For example, entering Do Mi So Mi Do produces a simple ascending-descending arpeggio.

Layer-Specific Interpretation

Uniform Solfège is interpreted differently depending on the active layer:

• Melody: Syllables can be interpreted as either absolute pitch positions within the solfège space or as interval movements from the previously sounded note (via Melodic Grammar).
• Harmony: Syllables represent vertical chord structures. The text parser allows for grouping multiple syllables to specify stacked notes, and a dash (-) can be used to explicitly pad or hold the harmonic field across rhythmic beats.
• Rhythm: Syllables strictly define rhythmic groupings and accents. Do and Di encode primary onsets and off-beats, without any attached pitch meaning.

MIDI Solfège Input

The MIDI Connect button in the text input bar initiates a WebMIDI API request. Once permission is granted, notes played on any connected MIDI device are automatically mapped to Uniform Solfège syllables and routed to the currently focused phrase editor. This makes the editor function as a transcription surface — play a musical idea directly on your instrument and see it rendered in Solfège notation in real time.

Layer-Aware Mappers & Input Octaves

The mapping strategy changes depending on which layer has focus. To facilitate both pitch selection and editing commands, the MIDI mapping divides the keyboard into two key regions: the Input Octave (C4 to B4) for note entry, and the Modifier Octave (C3 to B3) for structural commands and chord modifications.

• PitchMapper (Melody): Translates each incoming MIDI note in the Input Octave to its Uniform Solfège syllable relative to the root. Single notes map to single glyphs. Suitable for step-by-step melodic entry.
• HarmonyMapper (Harmony): Translates MIDI notes into stacked Solfège tokens. The lowest note played in the Input Octave defines the root of the chord, while additional notes held in the Modifier Octave specify the chord tones relative to that root. When you release all notes, or press the commit modifier, the chord is committed. Holding C3 in the Modifier Octave allows entering dot or dash padding symbols.
• RhythmMapper (Rhythm): Converts MIDI note timing into rhythmic tokens. Notes map to Do (onset) or Di, allowing you to tap a rhythm pattern directly on your instrument without needing dedicated rhythmic hardware.

General Modifier Keys

When using MIDI input, the Modifier Octave (C3 to B3) contains dedicated keys for editing and controlling the flow of syllables:

• E3 (Delete): Acts as a backspace to delete the last entered syllable in the active row.
• G3 (Commit): Explicitly commits the currently held chord or syllable to the phrase.

Structural Command Chords

Beyond note input, a special structural chord allows you to trigger structural editing commands without lifting your hands from the instrument. Hold C3 + B4 simultaneously, then press one of the following modifier notes:

MIDI input requires browser support for the WebMIDI API. Chrome and Edge support this natively. Firefox requires the Jazz-Plugin or similar. iOS/Safari is not currently supported.

Playback Engine

The playback system in this demo consists of cooperating headless components that live inside the <ppt-coil>. When you press Play, the transport publishes the current BPM and loop settings. The playback scheduler receives this, reads the rhythm layer's tokens to generate a timing grid of note onsets (or falls back to a 16-sixteenth-note grid if the rhythm layer is empty), then maps each melody and harmony token onto an onset and schedules the corresponding audio.

The synthesizer handles the actual audio synthesis, receiving events with frequency and duration from the scheduler. Multiple voices can be defined — one per row — to give each row its own timbre and register.

Mixer Controls

The <ppt-coil-mixer> wrapper injects Mute (M) and Solo (S) buttons into the header slot of each row. These are not just visual — mute/solo state is published to the EventBus and the PlaybackScheduler respects it when building the schedule. If any row is soloed, only soloed rows sound; if a row is muted, it is excluded from the schedule entirely.

In this demo, the Rhythm layer starts muted. You can unmute it once you have rhythm tokens entered to hear the full three-layer texture. The Mute button on the Rhythm row is highlighted red to indicate default-muted status.