A Case Study on Road Noise Sound Characteristic Identification and Improvement in a Sedan Based on Binaural Transfer Path Analysis

In recent years, road noise performance has attracted more and more attention during the development of vehicle NVH performance. However, how to effectively diagnose and optimize of vehicle road noise issue, which is a systemic problem has been a hot research topic in the industry. This paper describes the sound characteristic identification and improvement of road noise in a sedan based on binaural transfer path analysis (BTPA). First of all, by filtering and playing back the tested sound signals in a professional playback room, three clear frequency ranges with dominant customer perception have been identificated. They are a 75Hz-85Hz "drumming noise" accompanied by booming noise, a 100Hz-120Hz "buzzing noise" and a 200Hz-230Hz "cavity noise" caused by tire sound cavity modal. Then, according to the binaural transfer path analysis, a systematic analysis of "source-path-response" is carried out for each characteristic sound path, and the most valuable optimization is found by combining CAE simulation analysis and BTPS-based virtual prediction. Finally on-road assessment resulted in a significant improvement in sound pressure level/speech intelligibility objectively as well as subjectively.