Detection and Scaling of Squeak & Rattle Sounds

Squeak and rattle (S&R) noise is an important issue in the automobile industry because the presence of audible S&R in a vehicle can convey the impression of poor quality to the customer. Furthermore, addressing S&R problems can be a significant warranty cost issue. Overall-all level types of noise assessment, such as dB SPL and loudness, are not always suitable measures for S&R detection, characterization and scaling. This is primarily due to the highly dynamic temporal and localized spectral characteristics of most S&R events. In this report, Fourier and filterbank methods for the analysis of S&R events are considered, and several criteria for the detection and scaling of S&R noise are examined using data measured both in an ultra-quiet laboratory situation and in several realistic, on-road driving conditions. Recommendations are made for an analysis method that is robust across both laboratory and on-road measurement conditions.