The Operational Acoustic–Affective Space (OAAS): a framework for the design and evaluation of functional affective sound environments

Sound shapes emotional, behavioral, and physiological states in living systems. Despite growing evidence that humans and other animals respond affectively to sound, most research still relies on exposure-based paradigms and lacks translational, design-oriented methods—particularly in animal models where affect must be inferred from objective indicators. Consequently, links between acoustic structure and affective modulation remain weakly formalized, limiting reproducibility and cross-study comparability across heterogeneous sound sources. We introduce the Operational Acoustic–Affective Space (OAAS), a framework for designing and evaluating functional affective sound environments. OAAS defines a shared coordinate space in which sound environments can be positioned, compared, and intentionally modified relative to regulatory objectives. Rather than prescribing specific aesthetic forms or restricting inputs to pre-existing human music, the framework provides a coordinate geometry derived from objective acoustic descriptors and biologically grounded affective anchors, enabling interpretable analysis and controlled navigation within acoustic systems. We demonstrate OAAS using porcine-centered case studies that (1) define biologically grounded vocalization-derived reference anchors within a joint acoustic embedding space, (2) situate a veterinary functional music program for post hoc interpretation, and (3) validate operability through directed acoustic transformations that produce measurable displacement toward predefined affective reference regions. OAAS provides an extensible basis for translational affective sound design across species and contexts.