Subject movement during the measurement of head-related transfer functions
* Presenting author
In recent years, the need for individually measured head-related transfer functions (HRTFs) has increased steadily. To fulfil this need, current research offers various approaches to develop less time-consuming alternatives to prior measurement methods. As measurement inaccuracies due to subject movement may influence the quality of the acquired HRTFs, best possible conditions are desirable as well as a detailed knowledge of uncertainties occurring during the measurement. In this paper, it is explored how and to what extent subjects move during the measurement procedure. All measurements were conducted with a fast measurement set-up constructed at the Institute of Technical Acoustics, RWTH Aachen University. Four different types of measurement are compared in order to examine which one results in least movement. Three set-ups comprise one measurement with a sitting subject, another one with a standing rotated subject and a last one with a standing, not-rotated subject with the measurement arc rotating around the subject. The last set-up contains a real-time feedback system that allows the subject to perform a correction of position and orientation. The experiment revealed that most movement occurred with the subject’s orientation. Position inaccuracies have only negligible influence. With the visual feedback, all movements could be restricted within small constraints.