Impact Sound Evaluation Base on Two Dimensional Sound Indexes

In the previous paper [1], the impact sound metric is developed for the evaluation of the impact noise in passenger cars based on the wavelet transform. In this paper, seven semantics are subjectively evaluated by 25 participants based on semantic difference method. Two major factors are selected for important factors of impact noise in passenger car. One is comfortable, the other one is impulsive. Two sound indexes for impulsive and comfort are considered for the evaluation of impact sound when a car is driven on 7 difference road surface. These indexes are developed based on new sound metric and other major sound metrics like loudness, fluctuation strength, etc. For the development of these indexes, the interior sounds of 15 passenger car are measured by using artificial head and evaluated subjectively by the participants. These two indexes are successfully applied to the improvement of the impact sound in a test vehicle.