A Prediction Model Of Auditory Source Width Based On Loudness Level,Interaural Cross-correlation Coefficient And Center Frequencies

Auditory source width(ASW)is the perceived width of an auditory event of a stimulus,which has been long studied in room acoustics.In concert halls,the interaural cross correlation,the lateral fraction and the sound pressure level affect the perception of apparent source width.The prediction model including these factors is suitable for the perception of auditory sound field width in the large space hall,but not for scenes where audio is played back via headphones.As playing back audio via headphones,the perception of the auditory sound field width is significantly affected by the loudness level,interaural cross-correlation coefficient(IACC),and frequency bands.In this thesis,the relationship between the perception of ASW and the loudness level,the IACC and the frequency bands via headphones are studied.The main work is shown as follows:Firstly,based on the existing sound field width calibration methods,the virtual acoustic pointer is introduced as the reference signals to investigate the relationship for headphone users and different source signals are compared to find the most suitable signal.The broadband white noise is selected as the virtual source signal used finally,which is convolved with the HRTF datas from MIT to obtain virtual acoustic coordinates.Secondly,a subjective listening experiment was performed for the octave signals with the loudness level between 60 and 80 phons and the IACC between 0 and 1.The experimental results show that increasing the loudness level increases the ASW,but with different degrees at different frequencies.The minimum ASW increment appears around 1600 Hz and the maximum occurs around 200 Hz.The average of the ASW increment is approximately 5.4 degrees for 10 phons loudness increment.Decreasing IACC can broaden the ASW,the maximum of the increment of ASW occurs around 400-800Hz and the average increment is approximately 4.8 degrees for the decrement in IACC of 0.2.Finally,the multivariate variance calculation is carried out on the experimental results,and the interaction between the factors is analyzed.Based on the experimental results and the variance analysis results,a formula is developed by curve fitting to describe the relationship among the three factors and the ASW.The verification experiment shows that the error between the model and the experimental results is about 5°,which meets the accuracy requirements of the experiment,and can effectively predict the ASW of a fixed signal.The model can be applied to predict the auditory source width of a stimulus with fixed loudness level,fixed IACC and fixed center frequency.Three equal ASW contours were determined by the perceived model and are provided for reference.