Measurement of the Sound Transmission Loss of Rubber Seals Via the Aperture in Sound Barrier Fixture

A series of experiments was conducted to evaluate the sound transmission loss of rubber seals that are used in a dash panel of vehicles. Experiments were performed on several rubber specimens using the acoustic intensity method and compared with the predicted values that were obtained from the statistical energy analysis (SEA). Typically, to measure the sound transmission loss of a rubber seal such as an electrical wiring grommet, a specimen is assembled in an aperture of the sound barrier fixture and installed in an opening between a reverberation chamber and an anechoic chamber. Depending on the performance of the sound barrier and the sound pressure level of the source, the sound transmission loss measurement of the seal may contain significant errors. This study aims to investigate several factors that can cause errors when following the previous measurement methods and propose some experimental strategies to compensate them. Each experimental procedure was modelled using SEA for simultaneous verification of the experiment and simulation showing a good correlation. The tests were conducted under international standard ASTME90 conditions.