Research On Analysis And Evaluation Method Of Vehicle Interior Sound Quality Based On Binaural Auditory Model

The paper is based on Jilin Province technology development project"Analysis and Control of The Interior Roar and Wind in a Car", and the research is carried on. Vehicle engineering, acoustics, signal processing and other subjects are involved in this paper, and these subjects are cross-application in this paper. Binaural auditory model, sound quality of subjective and objective evaluation methods, the impact of sound quality of interior noise identification and sound quality control are systematically analysize and researched. The main works completed in the paper are as follows:This auditory model is designed to match the processing within the human auditory system as closely as possible. The auditory processing is applied to transform the corresponding sound signals to an internal representation, which is thought of as the information that is accessible to higher neural stages of perception. The whole model is demonstrated using known human performance data. The objective evaluation method of sound quality based on binaural hearing model is proposed, and the method is researched at the same time.Next, the vehicle interior noise which has been processed at the condition of uniform speed is taken as research object. Subjective appraisal result of the sound samples, the corresponding four psychological acoustic parameters and three kinds of different sound pressure are relatively analyzed in this paper. The result indicates that loudness, sharpness and roughness have strong relevance with the subjective appraisal result at the condition of experimentation in this paper. Also the vehicle sound quality index is better described by psychological acoustics parameters than every kind of pressure. Binaural loudness and subjective appraisal correlation coefficient achieve 0.904, which is 0.017 above the single-ear loudness and subjective appraisal correlation coefficient. Binaural loudness model and subjective sensation are more approximate.Through multiple linear regression analysis, a quantitative description of the subjective evaluation results of sound quality mathematical model by psychoacoustic objective parameters is established, and it has passed all kinds of tests.Analysis shows that interior sound quality is affected by the two parameters of loudness and sharpness at the steady-state average driving conditions, and loudness plays a significant role in both of the parameters. Which ever is more significant role in loudness. So the car to improve sound quality objective should focus on these two parameters. So the improvement of the vehicle interior sound quality should focus on both of the parameters.Finally, the car is evaluated , sound quality is estimated, decisive factors which are affected by loudness and sharpness are found by the sound quality mathematical model.Noise source of the strong reverberation sound field vibration surface is identificated by reactive sound intensity measurement. The software of calculition of reactive sound intensity and mapping of sound intensity are developed by MATLAB. The shortcoming of negative sound intensity is overcomed at the time of noise source identification of the strong reverberation sound field vibration surface, and the failure of the noise source identification is overcomed too. The positon of the noise source of the strong reverberation sound field vibration surface are acurately located and diognosised. And the two parameters are concerned with the combustion engine and the engine noise of the second resonance.The factors which are affected by vehicle interior noise are analyzed by the experimentation, vehicle interior noise is tested and analyzed by complex sound intensity scan, and the main resource of the interior noise is identified. The weak tache of the airproof and sound insulation is found through optimal configuration of engine mount and test of firewall airproof, and the measures of sound absorption and insulation are taken through selecting suitable acoustic absorption and insulation materials. The interior sound quality is analyzed and contrasted at the condition of the measures having been taken or not. The result shows, the loudness and sharpness of the interior noise is obviously improved after the noise reduction measures have been taken, the sound quality of interior noise is obviously improved. Vehicle interior sound quality is validated by the model SQ of sound quality evaluation index, the result shows that the interior sound quality is improved over 15%, and it is satisfied too, it further validated that sound quality objective evaluation model can guide the vehicle interior sound quality.