Spectral Behavior Transfer: Cross-Signal Transfer of a Temporally Regularized Frequency-Space Dynamical Operator

Spectral Behavior Transfer (SBT) investigates a cross-signal audio transformation in which the transferable object is neither spectral content nor a static spectral mapping, but a time-varying dynamical rule inferred from spectral motion. A Source signal A is analyzed into trajectories in logarithmic frequency space, from which a compact local dynamical operator is estimated. Source A is then removed, and the learned operator is used to evolve the spectral components of an unrelated Target B. The production implementation studied here is LAW, an experimental spectral-processing system in Harmonic DAW. Controlled synthetic experiments examine source removal, spectral tracking and identification, renderer realization, destructive controls, cross-source specificity, invariance to dynamics-preserving acoustic transformations, and sensitivity to genuine changes in latent dynamics. In an eight-law benchmark, all eight rendered targets were most strongly associated with their matched source-derived law. In a 4-motion × 4-nuisance factorial experiment, nearest-neighbor rendered behavior grouped by latent motion in 16/16 cases and by nuisance identity in 0/16 cases, with mean within-motion correlation 0.978 versus 0.369 between motions. The experiments also identify an important limitation: discrete fallback capture regimes can introduce representation discontinuities under otherwise dynamics-preserving changes such as source register. Several research-only remedies were tested but did not satisfy the required no-collateral-damage criterion, so no production modification is proposed. The resulting claim is deliberately constrained: within the controlled synthetic domain and identifiable capture regimes studied here, SBT provides evidence that a source can contribute a time-varying spectral-motion operator rather than its spectral material to the evolution of another sound. Natural-recording generalization and perceptual superiority are not claimed. Implementation: LAW, Harmonic DAW.DOI: 10.5281/zenodo.22873152