Effects of different head and torso orientations on the head-related transfer function

The head-related transfer function (HRTF) characterizes the spatial properties of sound arriving at an individual’s ears and is widely used in binaural audio and auditory research. HRTFs are typically measured—either through physical experiments or simulations—under the assumption that the head and torso are oriented in the same direction, or by ignoring the effects of the torso altogether. In this study, we investigate how differences in orientation between the head and torso affect HRTFs, using an established HRTF database. HRTFs were compared under conditions in which the positions of the head and the sound source were fixed and only the torso was rotated in the azimuthal direction. The results confirmed that changes occur over a wide frequency range, including notches and peaks due to the pinna. These findings suggest that accounting for dynamic postural changes can improve the realism of binaural rendering and enhance the accuracy of personalized HRTF modeling.