Anthropometric Parameters Influencing Head-Related Transfer Functions

This study deals with the question of how much influence the head, torso, and pinna dimensions have on spatial hearing, particularly as far as children and their growth are concerned. A statistical analysis of head, torso, and pinna dimensions of subjects including children and adults of all ages has been conducted for the first time to create a detailed database. Spatial cues are derived from CAD¹ models of the head using the Boundary Element Method (BEM) with a basic simplified model. Anthropometric parameters for the head and torso (height, breadth, length, and the distance from the ear to the shoulder) and for the pinna (height, breadth, and rotation angle, and cavum concha height, depth, and breadth) are analyzed and their effects are discussed. Varying each parameter individually makes it possible to isolate the effect of this parameter on the HRTF and on the spatial cues. The same approach is taken for various incidence angles. As far as the future construction of artificial heads for specific groups of population, including various ages, is concerned, the results presented here show where larger tolerances are acceptable regarding the different dimensions and where the dimensions should be chosen more accurately.