GMNA GM2223M PDF

1 SCOPE.

This specification describes the acoustical performance of the various noise control materials, along with methods and procedures for performance evaluation. In addition to identifying a minimum performance for these materials, this specification also provides a baseline reference against which new or unconventional materials can be evaluated. This specification is limited to material performance. other acoustical requirements, not stated herein, may also apply, e. g., in-vehicle objective and subjective performance and the performance of composite materials and parts.