Sound quality evaluation of the impact noise induced by road courses having an impact bar and speed bumps in a passenger car

Abstract

Sound quality indices for impact noise are developed by using sound metrics and a subjective evaluation. A new sound metric for impact sound is developed on the basis of a continuous wavelet transform, which is a useful tool for the analysis of non-stationary signals such as impact noise. Two other conventional sound metrics related to sound modulation and fluctuation are also considered. In all, three sound metrics are employed to develop impact sound quality indices for several specific impact courses on the road. The indices are verified by comparing the correlation between the index output and results of a subjective evaluation based on a test. These indices are successfully applied to an objective evaluation for improvement in the impact sound quality for cases where some parts of the suspension system of the test car are modified.