Developing a Small Sample Facility for Testing Automotive Acoustical Materials at Low Frequencies

This paper discusses the development of a small sample test facility for properly evaluating the low frequency noise control performances of various automotive acoustical materials. Based on several tests conducted with 0.61 m (24 in) diameter samples, this facility is designed to operate in the frequency range of 35 Hz to 355 Hz. Near-field root-mean-square acoustic pressure and acoustic velocity were measured for this purpose, using a dual microphone probe. This methodology allows one to test acoustical materials without elaborate test facilities and without the need for any special acoustic test environment.