Research On Sound Quality Of Car Door Closing Noise

The research of sound quality dated from 1980s, which is caused by the strong demands of the products on the international markets, such as vehicles, household appliances, etc.The research of sound qualities became a newly developing field in resent years and it has extended to the Aviation, the Railway, the Highway traffic noise pollution, the Inhabitant environment. At the meanwhile, sound quality has been attracting the acousticians'attention. The research of sound quality is on its way. Although it has been made much progress in the world, there are a lot of deficiencies in this field. Most researches focus on the way to evaluate the sound quality but lack the right way to solve the manufacture process. Because of the difference between nations, we must erect the data of ourselves.This article analyzed and discussed the car door closing sound quality based on subjective and objective evaluation. The aim is by analyzing the characteristics of the impulsive sound to find the solutions of the door closing sound quality.Firstly, it gave a brief summary of the definition, basic theory and methods of sound quality. And introduced the research characteristics and current situation of the sound quality. This article also chose appropriate objective evaluation parameters of the sound quality, which combined the new international development of sound quality research. The calculation methods of steady and transient sound psycho-acoustic parameters such as loudness, sharpness were given in this article. And the results have proved that our calculation methods were effective and feasible.Secondly, this article described the subjective evaluation methods and details of the door closing sound quality. Then the subjective evaluations were implemented and the paired comparison method was selected as a subjective evaluation method. After carrying on the reliability of the experiment dates, this article used the Bradley-Terry model to calculate the merit values of the door preferences. And then derived the calculation model between the subjective preference and psychoacoustic parameters (such as loudness and sharpness) using multiple linear regression methods. After that, the methods were proved to be effective and provided a reference for the subjective evaluation of sound quality.At last, the basic door structure was analyzed, short time Fourier transform was used to analyze the frequency-time relation of the car door closing sound. And the combination of the four characteristics of impulsive noise and door structure is to find the factors, which influenced door closing sound quality. The door structure, which is less preferred in the subjective evaluation, was improved. Finally, through the sound quality comparison between the doors, which was modified or not modified, the measures to improve our understanding of the door were proved to be effective and feasible. And the door closing sound quality was improved eventually.