This study conducts a multidimensional technical analysis of the Sendai New Music Hall (Interim Proposal)—a large-scale public infrastructure project with a projected budget of 64.6 billion yen. By utilizing the international standard ISO 3382 as a primary evaluative framework, this paper examines the acoustic quality requirements beyond conventional reverberation time (RT), incorporating multidimensional indices such as Sound Strength (G), Clarity (C80), and Inter-Aural Cross-Correlation (IACC). Furthermore, this analysis integrates ISO 9001 Quality Management Systems (QMS) to propose a governance model for public procurement, ensuring that specialized technical specifications translate into tangible public goods. The objective is to establish a standardized “technical language” to mitigate information asymmetry among municipal authorities, architects, and citizens, thereby ensuring the long-term acoustic and operational excellence of the facility. Disclosure: Declaration of Neutrality and No Conflict of Interest Declaration of Interests: The author declares that no conflicts of interest (COI) exist between the author and any administrative organizations, design firms, construction companies, or individuals involved in this project. Status of Research: This document is authored from a neutral standpoint as a "citizen researcher". It is intended solely as an academic and technical record based on scientific findings to serve as a baseline for future retrospective evaluations. This analysis does not intend to criticize any specific organization but aims to provide objective literacy for public quality verification. Keywords: ISO 3382, ISO 9001, Sendai New Music Hall, Architectural Acoustics, Public Policy, Quality Management System (QMS), Public Procurement.