Design, Manufacturing and Validation of a Test facility for transmission loss measurement

Traditional methods of measuring sound transmission loss (STL) of acoustic materials and treatment are time-consuming and expensive. To overcome this limitation, normal incidence transmission loss measurement technique using an impedance tube has been developed. This paper presents an effort made to design and build a cost-effective impendance tube as per the ASTM E2611-09. Standardized measurement uses a plane wave tube instrumented with four microphones and a termination consisting of an adaptable acoustic load. The mathematical formulation is based on the transfer matrix representation (TM method). In order to validate the proposed model design, a numerical/experimental correlation is presented. Numerical model is obtained using the Finite Element Method (FEM). Therefore, the test facility operation has proved reliable.