2025-06-04

inertia

models temporal persistence, memory, and resistance to change in sonic behavior. governs how voices accumulate activation pressure and how quickly they respond, recover, or fade. inertia introduces structured lag, hysteresis, and buildup effects that allow musical elements to "stick," "settle," or "fade in/out" organically, while remaining fully deterministic.

introduction

this domain encodes per-voice temporal momentum - simulating concepts like:

  • delayed entry or recovery
  • fatigue or buildup
  • lingering presence
  • gradual fade or resistance to change unlike constraint, which is quota-based, or pressure, which is momentary, inertia tracks internal state over time - without using feedback or runtime logic. instead, all inertia curves are precomputed, based on incoming trigger structure or segment duration.

overview

  • 0 exponential rise/fall

    • description: smooth ramp-up and decay around trigger activity
    • analogy: steam pressure, mental focus, energy
    • notes:

      • a: rise time (0 = fast, 1 = slow)
      • b: decay time (0 = fast, 1 = slow)
  • 1 decay on silence

    • description: maintains level while active, decays only on inactivity
    • analogy: presence that “fades out” after last event
    • notes:

      • a: decay time
      • b: hold threshold (0 = decay immediately, 1 = delay longer)
  • 2 burst memory

    • description: rapid gain from each trigger, slow fade
    • analogy: bubbling energy, bursting behavior
    • notes:

      • a: burst size per trigger
      • b: decay time
  • 3 refractory window

    • description: temporary suppression after each trigger
    • analogy: neural refractory period, fatigue
    • notes:

      • a: suppression strength (0 = light, 1 = full mute)
      • b: duration of suppression (0 = short, 1 = long)
  • 4 crossover lag

    • description: voice competes with others and takes time to rise

    • analogy: filling a gap, bubbling to surface

    • notes:

      • a: inertia to enter (0 = instant, 1 = slow)

      • b: inertia to exit (0 = instant fade, 1 = long fade)

parameter behavior summary

  • exponential rise/fall

    • a: rise time
    • b: decay time
  • decay on silence

    • a: decay curve
    • b: silence hold
  • burst memory

    • a: gain per trigger
    • b: fade curve
  • refractory window

    • a: mute strength
    • b: mute duration
  • crossover lag

    • a: fade-in resistance

    • b: fade-out resistance

why these were chosen

each form captures a distinct musical inertia archetype:

  • rise/fall: general energy tracking
  • decay-on-silence: persistence after activity
  • burst memory: impulse-driven texture
  • refractory: suppression and fatigue
  • crossover: layered emergence of voices together they model both gradual processes and discrete resistances, essential to simulate presence, absence, buildup, and competition.

what is not included

  • feedback loops or runtime tracking (state must be precomputed)
  • probabilistic decay or noise
  • input-dependent state branches (e.g. "if 3 triggers in 5 beats…")
  • dynamic reweighting (handled by upstream domains)

conclusion

inertia adds a structured sense of presence, resistance, and memory to the onset engine. it enables musical elements to feel organic, “settled,” or “bubbling up” - without requiring runtime feedback. by shaping how voices linger, resist entry, or recover from activity, inertia supports naturalistic behaviors in both regular and chaotic textures.