Boundary element method calculation of individual head-related transfer function. II. Impedance effects and comparisons to real measurements.

Following previous work by the author involving the calculation of an individual head-related transfer function (HRTF) using a Boundary Element Method (BEM) approach, impedance conditions are now included to take account of the acoustic properties of human hair. In addition, comparisons are made here between calculations and measured values for the HRTF of a specific individual. Numerous works have been published regarding the measurement of HRTFs, but rarely are several methods compared for the same individual. The results presented in the work compare two different measurement techniques and a computational BEM for acquiring an individual HRTF. Impedance effects have been incorporated in the BEM model for hair based on measured data, providing a final set for comparison. Measurement results show significant variations for the same individual. Computational results show good agreement within the range of experimental variations. Definite trends are observed for many directions, while the limitations of the methods are also highlighted for others. The effects of incorporating hair impedance are shown to provide an improvement in the correlation of computational results, indicating an affect of hair impedance on the HRTF.