Research On The Characteristics Of Virtual Sound Image Localization Spectrum In Far And Near Field

The Head Related Transfer Function contains the main information of sound source localization,which is very important for the study of binaural hearing and psychoacoustics.The research shows that there are large differences in the HRTF spectrum between different far and near fields.However,it is difficult to obtain near-field HRTF data.In order to easily obtain near-field HRTF data and explore the differences in far-field and near-field localization spectrum characteristics,this paper has carried out The two aspects of work are as follows:First,two analysis methods(correlation coefficient method and spectral distortion method)are proposed to explore the similarity relationship between the far-and near-field localization spectrum features,with azimuth of the source far-field distance(r = 1.00m)(30°~180°,intermediate interval 30°)for reference,respectively,the similarity calculation with the three distances of the near field(r = 0.25 m,0.50 m,0.75m),because the middle and high frequency signals have a greater effect on the localization spectrum characteristics,the calculated frequency band is 3~15kHz,and the psychoacoustic experiment of the obtained near-field matching angle is carried out.The experimental results show that the two methods perform differently at different distances.From the distribution of the data curve,the difference in the positioning effect of the similarity angle calculated by the spectral distortion method and the correlation coefficient method is small,which means that both methods can be applied to the similarity analysis.Secondly,starting from the physical model,since the human head model is not a symmetrical spherical structure,it is closer to the ellipsoidal structure.Based on this,a simplified model of the ellipsoid is proposed,and the acoustic pressure calculation expression of the ellipsoid model and the rigid ball model is given.with the far field distance(r = 1.00m)7 directions(0°~180°,intermediate interval 30°)as the reference,applies the distance variation function on the rigid ball model and the ellipsoid model respectively.The ellipsoidal simplified model synthesis HRT and rigid sphere model synthesis HRTF and measured HRTF signal were tested by psychoacoustic experiments.The results show that the experimental results of the HRTF synthesis of the rigid sphere model and the experimental results of the ellipsoid model synthesis HRTF have a strong consistency with the experimental results of the measured HRTF.It means that the ellipsoid model is feasible and effective in synthesizing near-field HRTF.This work helps to understand the variation of the spectral features of HRTF with distance.The proposed near-field HRTF acquisition method based on human ellipsoid DVF can be directly applied to virtual sound reproduction in three-dimensional space.