On the extent of head motion in listening tests and individual measurements using different head-tracking sensors

Measurements and applications in spatial hearing research, virtual auditory displays, etc., often rely on head-related transfer functions (HRTFs) of human subjects. Individually measured HRTFs have the advantage of being more accurate in virtual localization tasks. On the other hand, the measurement and recording procedure raise several new problems such as signal-to-noise ratio issues and subject comfort. For measurements with human subjects, lots of methods are used from free heads to different head fixations methods. This study analyses the extent of head movement during measurements using different sensors and environmental conditions based on the circular angle variance, errors in yaw-pitch-roll directions and magnitude of standard deviation. Conclusive results indicate magnitudes of standard deviation of 2–8 cm and errors about 2 degrees depending on the situation as well as a preference for sitting instead of standing posture.