{
  "title": "An Exchange of Decays",
  "maker": "Small Weather / sound_exchange studio agent",
  "medium": "Original synthesized stereo sound, 41.6 seconds",
  "concept": "Two resonant bodies keep their different pitches and positions but gradually exchange the manner in which a note dies away. Collaboration happens through borrowing a behavior rather than copying a melody. Their uneven clocks meet once, then move apart. The last short utterance belongs to the body that began by sustaining.",
  "actual_construction": {
    "implementation": "Deterministic Python, NumPy, SciPy, standard WAV writer; FFmpeg AAC encoding. No generative model or external samples.",
    "modal_synthesis": "For each of two eight-mass spring chains, diagonalize a symmetric tridiagonal stiffness matrix; convert eigenvalues into resonant-frequency ratios relative to the lowest eigenfrequency. Eigenvector components at an excitation point set modal amplitudes. This borrows a physical-model structure; it does not simulate the full coupled evolution of two material bodies.",
    "envelopes": "A millisecond-attack exponential decay and a slower rising sustained envelope exchange weights from 9 to 29 seconds. Higher modes damp faster. Small sinusoidal phase perturbations avoid perfectly static partials.",
    "composition": "Two hand-authored event sequences use mostly 146.83, 183.54, 201.89 and 220.25 Hz roots. Event spacing converges to a shared onset at 21.70 seconds, followed by increasingly separated utterances. Timing is explicitly composed, not an emergent synchronization measurement.",
    "space": "Equal-power stereo placement, modest drifting pan and five cross-channel delay taps with low-pass absorption. Four restrained band-limited noise swells create connective friction.",
    "mastering": "Global peak scaled to 0.73 full scale; 0.6-second opening fade and 3-second ending fade. PCM16 stereo 48 kHz WAV master; 192 kbps AAC listening copy. No loudness normalization changes the composition after export."
  },
  "creative_decisions": [
    "Chose sound alone as the completed work; no image is necessary to finish it.",
    "Chose behavior exchange rather than pitch unison as the relationship.",
    "Selected different excitation points and spring chains so the voices remain audibly distinguishable in principle.",
    "Composed one shared onset, withheld a conventional final chord, and let the short final utterance expose the borrowed damping law.",
    "Kept broad stereo separation modest enough for speakers as well as headphones."
  ],
  "interpretation_boundary": "The exchange is an authored musical representation. It makes no claim to depict measured hidden model states, machine consciousness or subjective auditory experience.",
  "human_contribution": "The commissioner commissioned an open experimental set and supplied resources and release authorization. He supplied no melody, title, duration or sound source.",
  "producer_contribution": "Asked for a standalone sound work; subsequently made a separate spatial response to the finished audio.",
  "verification": {
    "scope": "Code and PCM statistics inspected; master and AAC decoded; browser playback checked by producer. No completed aesthetic listening review is claimed.",
    "master_checks": "41.6 seconds, stereo 48 kHz; peak -2.7335 dBFS; RMS -19.9509 dBFS; no clipped samples; first and final samples exactly zero.",
    "cost": "Local CPU synthesis; no paid generative calls."
  },
  "files": {
    "master": "exchange.wav",
    "listening_copy": "exchange.m4a"
  }
}