Research On Horizontal Auditory Localization And Related EEG In Reverberant Fields

Compared with the free field condition,the presence of reverberation（including early and late reflections）in indoor space improves the degree of sound externalization as well as the accuracy of auditory distance perception and enhances the reality of virtual sound stimulus.In addition,reverberation also has a certain impact on auditory localization.At present,there are some divergences in research of horizontal auditory localization in the reverberant field,which mainly includes:（1）whether the reverberation ha s a significant effect on horizontal auditory localization;（2）reverberation is beneficial or detrimental to horizontal auditory localization.To solve the above problems,the room size and reverberation time were controlled to construct room models with different reverberation times.The behavioral performance and related brain response mechanism of horizontal auditory localization in different reverberant fields were studied by auditory localization experiment and EEG experiment.Firstly,the personalized binaural room impulse responses in different reverberant field conditions were constructed by combining the personalized method of head-related transfer functions based on anthropometric parameter matching and multi-database integration with the simulation algorithm of the binaural room impulse response.The horizontal virtual sound sources with different reverberation times then were synthesized,and the auditory localization experiments were designed and implemented.Experimental results show that reverberation time and the azimuth of sound source are significant main factors affectin g the auditory localization performance of subjects,moreover,there is no significant interaction between reverberation time and the azimuth of sound source.Compared with the free field condition,the localization accuracy of subjects in reverberation time T₆₀=0.3s and 0.6s condition is significantly higher.However,with the increase of reverberation time,reverberation has a more and more severe influence on auditory localization performance,auditory localization significantly deteriorates in the condition of long reverberation(T₆₀=1.2s,1.5s).Then,using Event-Related Potential（ERP）as an indicator,the physiological mechanis m of auditory localization in the reverberant field was explored through auditory EEG experiments.The results of EEG experiments show that the amplitude of P300 component has a significant positive linear relationship with reverberation time and the azimuth of sound source.The amplitude of Mismatch Negativity（MMN）is the largest in the condition of appropriate reverberation(T₆₀=0.6s),and there is a significant positive linear relationship with the azimuth of sound source in the condition of free field and appropriate reverberation(T₆₀=0.6s).In addition,the amplitudes of MMN and P300 have a significant correlation with the azimuth perceived by the subjects and increase linearly with the increase of the perceived azimuth.Moreover,the value of Inter-aural Cross Correlation Coefficient（IACC）is also significantly correlated with MMN and P300,indicating that there may exist brain activities to analyze interaural correlation in the process of auditory localization.The results of this work are helpful to understand the mechanism of auditory localization in the reverberant field,provide the experimental evidence for the selection of optimal reverberation time in room acoustical design,and provide the experimental basis for ERP-based auditory brain-computer interface technology.