Melody Composer

Step 2: Design the Melody

Build from a motivic seed:

1. Create a short motif (3-5 notes) that captures the essence
2. Develop it: repeat, sequence (transpose), invert, extend
3. Shape the contour - build to a climax ~62% through, then resolve
4. Vary rhythms to avoid monotony

Melodic guidelines:

• Mostly stepwise motion, occasional leaps
• Large leaps resolve by step in opposite direction
• Phrase endings on stable scale degrees (1, 3, 5)
• Leave breathing room - silence is part of melody

Step 3: Generate the Composition

Create a JSON specification with one or more voices:

{
    "title": "Composition Title",
    "tempo": 90,
    "time_signature": [4, 4],
    "voices": [
        {
            "name": "Melody",
            "instrument": 0,
            "channel": 0,
            "notes": [
                {"pitch": 60, "duration": 1.0, "velocity": 80, "start": 0.0}
            ]
        },
        {
            "name": "Bass",
            "instrument": 32,
            "channel": 1,
            "notes": [
                {"pitch": 36, "duration": 2.0, "velocity": 70, "start": 0.0}
            ]
        }
    ]
}

Voice fields:

• name: voice identifier (for MIDI track name)
• instrument: General MIDI program number (see below)
• channel: MIDI channel 0-15 (use different channels per voice)
• notes: array of note events

Note fields:

• pitch: MIDI note number (60 = middle C, each semitone +1)
• duration: length in beats (1.0 = quarter note at tempo)
• velocity: loudness 0-127 (typical: 60-100)
• start: beat position where note begins

Common GM instruments:

• 0: Acoustic Grand Piano
• 4: Electric Piano
• 24: Nylon Guitar
• 32: Acoustic Bass
• 40: Violin
• 42: Cello
• 48: String Ensemble
• 56: Trumpet
• 73: Flute
• 88: New Age Pad

Step 4: Render Audio

Run the composition script:

echo '<json>' | python3 scripts/compose.py output_name --wav

This creates both .mid (MIDI) and .wav (synthesized audio) files.

Quick Reference

MIDI pitches (octave 4): C=60, D=62, E=64, F=65, G=67, A=69, B=71

Common scales from C (60):

• Major: 60, 62, 64, 65, 67, 69, 71
• Minor: 60, 62, 63, 65, 67, 68, 70
• Pentatonic major: 60, 62, 64, 67, 69
• Dorian: 60, 62, 63, 65, 67, 69, 70

Emotional intervals:

• Minor 3rd (3 semitones): sadness
• Major 3rd (4): joy
• Perfect 5th (7): power, stability
• Minor 6th (8): longing

For complete theory, see references/music-theory.md.