Virtual Acoustic Object (VAO) Standard: Version 0.4.0

The Virtual Acoustic Object (VAO) Standard 0.4.0 is an open exchange and preservation standard for digital representations of musical instruments and other acoustic objects. It defines a JSON manifest, a safe ZIP-based .vao carrier, optional domain profiles, and a linked-data projection without replacing the established formats used for the represented resources. VAO can connect descriptive metadata, measurements, recordings, images, 3D models, interaction data, provenance, rights, and exact file identities as one coherent, transferable, and preservable release. This source bundle contains the normative specification, conformance and security requirements, JSON Schemas, JSON-LD context, RDF vocabulary, SHACL shapes, domain profiles, fixtures, reference tools, tests, and implementation guidance. VAO is an integration envelope rather than a renderer, repository service, ontology-reasoning regime, cryptographic trust infrastructure, or rights decision engine. Conformance establishes adherence to the declared structural and semantic rules; it does not certify that a measurement, simulation, interpretation, attribution, rights assertion, or represented object is empirically true or scientifically adequate. VAO 0.4.0 includes a conservative mapping to MODAVIS Ontology Network 0.1.0. The ontology supplies stable semantic identifiers, while core VAO validation remains self-contained in the VAO schemas and specification. This software was developed during the PhD project MODAVIS (2022–2026), supported by the German Academic Scholarship Foundation (Studienstiftung des deutschen Volkes).