The Investigation In Bus Interior Sound Quality Control And Dynamic Evaluation Indexes

The sound quality of vehicle originated from 1980 s, as one of important component parts of the NVH properties, sound quality is an evaluation standard of the vehicle interior sound environment. And it is an important evaluation standard for the customer choosing a vehicle. In this paper, a city bus was chosen as the object vehicle, the bus interior sound quality control and the bus interior sound environment construction based on the masking effect had been investigated. The relationship between subjective and objective indexes had been analyzed with grey relation analysis method, three synthetically indexes for the bus interior dynamic sound quality objective evaluation considering masking effect had been built. These indexes can be used to select the masking sound which be used to control the bus interior sound quality.First, research status of the vehicle interior sound quality and the subjective and objective evaluation method had been introduced. And then, the framework and research contents had been determined. Combining with previous research the theory of subjective and objective sound quality evaluation had been introduced. At the same time, the masking effect theory and the control theory of sound quality by masking effect had been introduced too. Base on those theory and the research characteristics the control scheme of dynamic sound quality had been design.Second, combining with previous research the sound quality objective and subjective evaluation method had been designed and the experiment had been done. The working condition, the masking sound and the sound pressure level were selected as three factors which possible most important affected the bus interior masking sound environment to design the experiments. Considering the time and workload of jury test members we use the orthogonal experimental designing to optimize the experiments. The noisy, acceptability and anxiety had been introduced as the subjective evaluation indexes to reflect the bus interior sound quality. Beside the psychoacoustic indexes the variance and range of each psychoacoustic index had been introduced into the objective evaluation as the dynamic indexes.Third, the relationship of the subjective and objective indexes had been analyzed based on grey relation analysis method. The effect factor of objective indexes for the subjective evaluation had been found, and the weight of each objective evaluation index had been assigned. At last, the synthetically indexes for the bus interior dynamic sound quality objective evaluation considering masking effect had been constructed. The 3D vector spatial contrast error analysis had been used to test the synthetically indexes.Finally, based on engineering psychology and musical psychology 75 masking sound environment had been designed, the appropriate masking sound had been selected according to the synthetically indexes to control the bus interior dynamic sound quality. At the same time, the sound field control system had been designed renewably and the appropriate speakers had been selected to play the masking sound. The purpose of this is to control the object vehicle interior sound quality.