Title: A Study on the Rattle Index from a Vehicle Door Trim under Audio System Inputs
text: The sound inside a passenger cabin is composed of many elements, which include irritating noises such as buzzes, squeaks and rattles. Customer perception of buzz, squeak and rattle (BSR) is measured by Things Gone Wrong (TGW), warranty claims and JD Power surveys.1) The Speaker BSR test has been adopted to evaluate and to eliminate rattle noise of a door module while playing sound through the audio system. Subjective listening had been the preferred method for rattle noise detection, due to the sound of the audio system in any measurement. In this paper a quantitative approach for the rattle noise under the speaker test is proposed. The HANIL E-HWA rattle index was developed using a high pass filter, hiss noise reduction filter, SPL data with short time constant, peak value and fluctuation. The high pass filter was adopted to separate the rattle noise from the speaker sound, due to much higher sound pressure level [108 dB(A)] in the latter case. It is then possible to quantify the rattle noise by the HANIL E-HWA rattle index based on the peak values and fluctuations of the SPL data in the speaker BSR test. This article includes test results which show the improved rattle noise detection capability of the HANIL E-HWA rattle index.