A Study on North American Customer Preference to Interior Noise using Sound Balance Analysis

A new approach to achieve better customer perception of overall vehicle quietness is the sound balance improvement of vehicle interior sound during driving. Interior sound is classified into 3 primary sound source shares such as engine sound relative to revolution speed, tire road noise and wind noise relative to vehicle speed. Each interior sound shares are classified using the synchronous time-domain averaging method. The sound related to revolution order of engine and auxiliaries is considered as engine sound share, tire road noise and wind noise shares are extracted by multiple coherent output power analysis. Sound balance analysis focuses on improving the relative difference in interior sound share level between the 3 primary sound sources. Virtual sound simulator which is able to represent various driving conditions and able to adjust imaginary sound share is built for several vehicles in same compact segment. Objective sound evaluation targeting the North American customer is carried out using the virtual sound simulator tool in audio lab and it is verified that overall customer perception is improved by modification of sound balance between 3 primary sound shares. Through objective evaluation for the North American customer, the effectiveness of each sound source to each driving condition and customer perception of overall quietness and preference was found. In this paper the development guideline for interior for the North American market is suggested as well as effective countermeasures for improving sound balance.