Applying time domain equivalent sources to the computation of head related impulse responses and transfer functions Structural Acoustics and Vibration: Paper 5aSAa10

Head-related impulse responses (HRIRs) and transfer functions (HRTFs) have primarily been computed using frequency-domain boundary element methods or finite-difference time domain methods. The possibility of computing HRIRs and HRTFs using transient equivalent sources is examined here using a lumped parameter technique for enforcing the specified boundary condition. The computation is performed as a scattering problem with rigid boundary conditions specified for the surface of the head and torso. It is shown that performing the computations in the time domain is advantageous because only a few thousand time steps are needed to fully define the HRIRs. In addition to uniform meshes sized for different upper frequencies, the possibility of performing the computations using a nonuniform mesh is also explored. Comparisons between direct and reciprocal computations are given to demonstrate solution consistency. Various tests are performed to illustrate the variation in the solution with time step size and inner ear receiver position. The numerical results show that the various meshes produce consistent solutions except with some discrepancies in predicting HRTF minimums. It is also shown that the computations adapt well to parallel processing environments and the times associated with computing the matrices and convolution summations are proportional to the number of processors.