Spiral Pitch Dance — User Guide
Geometric pitch motion: creates accelerating spiral pitch movements with smooth, mathematical curves for dynamic vocal and instrumental effects.
What this does
This script implements spiral pitch dance — a geometric approach to pitch modulation that creates accelerating spiral movements through pitch space. Generates smooth, mathematically-defined pitch curves that spiral outward with increasing speed, creating dynamic pitch arcs that evolve over time. Process builds accelerating phase functions and applies them to create spiral pitch contours with precise control over rotation speed and range.
Key Features:
- 8 Spiral Presets — From gentle arcs to extreme spirals
- Accelerating Motion — Pitch changes speed up over time
- Geometric Curves — Mathematical spiral functions
- Smooth Transitions — Dense sampling for fluid motion
- Range Control — Precise semitone range definition
- Musical Foundation — Exponential pitch mapping
What are spiral pitch movements? Traditional pitch effects: vibrato (periodic oscillation), glides (linear transitions). Spiral dance: accelerating pitch arcs that create geometric motion through pitch space, inspired by mathematical spirals and accelerating rotational motion. Advantages: (1) Dynamic evolution: Pitch changes accelerate, creating narrative progression. (2) Geometric precision: Mathematical curves ensure smooth, predictable motion. (3) Musical expressivity: Creates dramatic pitch arcs and builds. (4) Flexible intensity: Parameters control spiral tightness and range. (5) Clean implementation: Dense sampling prevents artifacts. Use cases: Vocal processing, instrumental effects, sound design, film scoring, experimental music, dynamic builds.
Quick start
- Select Sound object in Praat (monophonic content works best)
- Run
spiral_pitch_dance.praat - Choose preset for immediate spiral types
- Adjust spirals (1-8) for number of rotations
- Set semitone_range (12-60) for pitch variation amplitude
- Configure acceleration (1.2-3.0) for speed increase rate
- Click OK — spiral dance applied to "originalname_spiral"
Quick tip: Start with Moderate Spiral preset for balanced results. Use Gentle Spiral for subtle arcs, Extreme Spiral for dramatic effects. Higher spirals create more rotations but may sound busy. Moderate acceleration (1.5-2.0) creates natural-sounding speed increases.
Spiral Theory
Accelerating Phase Algorithm
🌀 Spiral Motion Mathematics
Core algorithm: Accelerating phase function with exponential pitch mapping
# Normalized time position
pos = current_time / total_duration
# Accelerating phase calculation
phase = spirals * 2 * π * (pos ^ acceleration)
# Spiral oscillation value
spiral_value = sin(phase)
# Pitch shift in semitones
pitch_shift_st = semitone_range * spiral_value
# Convert to frequency ratio (exponential mapping)
ratio = 2 ^ (pitch_shift_st / 12)
# Apply to base frequency
new_f0 = median_f0 * ratio
Result: Smooth, accelerating pitch arcs that spiral through musical space
Mathematical Components
| Parameter | Role | Effect |
|---|---|---|
| spirals | Rotation count | More spirals = more pitch oscillations |
| semitone_range | Pitch amplitude | Larger range = wider pitch excursions |
| acceleration | Speed increase | Higher values = faster acceleration |
| timestep | Analysis precision | Smaller values = more accurate pitch detection |
| floor/ceil | Pitch limits | Frequency range clamping |
Acceleration Behavior
Acceleration effects:
acceleration = 1.0: Linear motion (constant speed)
phase grows linearly with time
even pitch oscillation speed
acceleration = 1.5: Moderate acceleration
phase grows faster over time
pitch oscillations speed up gradually
acceleration = 2.0: Quadratic acceleration
phase grows quadratically
noticeable speed increase
acceleration = 3.0: Extreme acceleration
phase grows cubically
rapid speed increase, dramatic effect
Typical musical range: 1.2-2.5
Creates natural-sounding acceleration
Avoids mechanical or extreme behavior
Spiral Presets
| Preset | Spirals | Range (st) | Acceleration | Character |
|---|---|---|---|---|
| Gentle Spiral | 1.5 | 12 | 1.3 | Subtle, slow arcs |
| Moderate Spiral | 2 | 24 | 1.5 | Balanced spiral motion |
| Aggressive Spiral | 3 | 36 | 1.8 | Energetic, fast-moving |
| Extreme Spiral | 5 | 48 | 2.2 | Dramatic, wide excursions |
| Fast Rotation | 4 | 30 | 2.5 | Rapid, spinning motion |
| Slow Evolution | 1 | 18 | 1.2 | Gradual, unfolding arcs |
| Psychedelic Swirl | 8 | 60 | 3.0 | Intense, disorienting |
🎵 Creative Applications
Gentle Spiral: Vocal expression, subtle pitch movement
Moderate Spiral: Instrumental effects, musical phrasing
Aggressive Spiral: Electronic music, dynamic builds
Psychedelic Swirl: Sound design, special effects
Applications
Musical Expression
Vocal Processing: Apply Gentle Spiral to singing for natural-sounding pitch arcs that evolve over phrases, creating expressive vocal lines without mechanical vibrato.
Instrumental Effects: Use Moderate Spiral on sustained instruments like strings or synths to create dynamic pitch movements that build energy over time.
Build-Ups and Transitions: Aggressive Spiral creates accelerating pitch rises perfect for electronic music build-ups, film score tension, or dramatic transitions.
Sound Design
Dynamic Motion: Spiral pitch movements create a sense of geometric motion through audio space, ideal for sci-fi effects, spinning objects, or abstract soundscapes.
Narrative Arcs: The accelerating nature of spiral curves naturally creates narrative progression, making them ideal for film scoring and dramatic audio contexts.
Technical Considerations
Monophonic Content: Works best with single-line melodies or solo instruments. Complex polyphonic material may produce unpredictable results.
Extreme Parameters: Very high acceleration (>2.5) with many spirals can create unnaturally fast pitch changes. Test with shorter audio segments first.
Dense Sampling: The script uses 200-2000 control points to ensure smooth spiral curves. Longer audio files automatically use more points for optimal quality.