Expressive coupling and textural dissociation in classical piano performance: evidence from the ASAP dataset

Performance science needs empirical methods that can connect musical interpretation with measurable behavior while preserving the musical meaning of skilled performance. This study examines expressive coupling between timing flexibility and dynamic shaping, together with textural dissociation from surface note density, in public classical piano performance using the Aligned Scores and Performances dataset. The analysis extracts beat interval variability, local tempo change, MIDI velocity dynamic range, and note density from aligned annotations and MIDI note events. Composer labels are then organized into broad repertoire groupings so that timing and dynamic behavior can be compared across repertoires. Results show clear differences among these groupings, with more flexible timing and wider dynamic shaping in Romantic and late Romantic repertoires than in Baroque repertoire. The central result is an expressive coupling between timing and dynamics: timing variability is closely associated with dynamic range. At the same time, global timing flexibility is dissociated from surface note density, because note density does not account for this timing behavior. A compact feature-based prediction procedure also performs reliably above a simple frequency baseline. These findings identify expressive coupling and textural dissociation as measurable features of pianistic interpretation, showing how temporal and dynamic control operate together while remaining distinguishable from surface note density.