2025-05-30

motion

continuous spatial movement: circular motion, LFO-driven panning, chaotic wander, or path-following.

introduction

The motion domain resides in the spatial layer and enriches static placements by assigning each source a precomputed, continuous trajectory through the sound field. It operates after position (static anchor) and before diffusion (spatial spread), generating time-varying coordinates for each voice or partial. All motion forms are deterministic-once parameters a and b are fixed, the full path is known prior to playback, with no runtime randomness or feedback.

overview

Each form defines a unique movement paradigm over a normalized time span:

0. circular_orbit

  • Behavior: moves the source in a circular or elliptical orbit around a center point
  • Analogy: a rotating speaker or a carousel ride

  • Parameters:

    • a: rotation speed (0 → 0 Hz … 1 → Nyquist-rate LFO)
    • b: orbit shape (0 = perfect circle → 1 = highly eccentric ellipse)

1. lfo_pan

  • Behavior: oscillates the pan position with a low-frequency oscillator
  • Analogy: a pendulum swinging left and right

  • Parameters:

    • a: LFO rate (0 → 0.01 Hz … 1 → 10 Hz)
    • b: modulation depth (0 = no movement → 1 = full stereo traverse)

2. path_follow

  • Behavior: traverses a user-defined static path (line, curve, or bezier spline)
  • Analogy: an object rolling along a drawn track

  • Parameters:

    • a: path selector/phase (0 → start of path … 1 → end of path)
    • b: traversal speed (0 → static at start → 1 → completes path in one cycle)

3. chaos_wander

  • Behavior: applies a chaotic or noise-based algorithm (e.g., logistic map, Perlin noise) to pan coordinates
  • Analogy: leaves blown randomly by the wind

  • Parameters:

    • a: complexity parameter (0 → near-linear drift → 1 → deep chaos)

    • b: wander amplitude (0 = no movement → 1 = full stereo width)

parameter behavior summary

  • circular_orbit

    • a: angular velocity of the orbit
    • b: ellipse eccentricity (radius ratio)

  • lfo_pan

    • a: oscillation frequency
    • b: pan excursion range

  • path_follow

    • a: phase along the predefined curve
    • b: speed scaling of the traversal

  • chaos_wander

    • a: nonlinearity strength (chaos vs. linear drift)

    • b: maximum positional deviation

why these were chosen

  • Comprehensive dynamics: covers cyclical, periodic, path-based, and chaotic movements-four archetypal motion paradigms.
  • Irreducible forms: no form can emulate another's behavior without external data or extra parameters.
  • Two-parameter clarity: split between tempo/speed and shape/extent in each case, preserving parametric purity.
  • Fully precomputed trajectories: aligns with the system's deterministic, additive ethos, ensuring every spatial coordinate is known in advance.

what is not included

  • Reactive or event-triggered moves: handled by structural or onset domains.
  • Audio-rate movement or micro-modulation: those would violate the “no post-processing” rule.
  • 3D spatialization curves or listener-tracking: outside current 2D pan-field scope.
  • Dynamic diffusion or blurring: delegated to the diffusion domain.

conclusion

The motion domain provides a succinct yet powerful set of four continuous movement forms-circular, LFO, path-based, and chaotic-each fully defined by two parameters. Together, they enable complex, deterministically repeatable spatial trajectories that expand the project's remit from static placement to rich, time-varying sound motion, without sacrificing the overarching goals of parametric purity and precomputed structure.