A DYNAMIC VIRTUAL AUDITORY DISPLAY: ITS DESIGN, PERFORMANCE, AND PROBLEMS IN HRTF SWITCHING

A software-implemented dynamic virtual auditory display (DVAD) has been developed by the authors. The DVAD responds to the listener’s head rotation by using a head-tracking device and switching head-related transfer functions (HRTFs), thereby presenting a highly realistic virtual auditory space to the listener. The DVAD operates on Windows XP and does not require high-performance computers. The measured total system latency of our DVAD is 50–60 ms, which is practically small enough for applications and localization experiments. The occurrence of click noises due to HRTF switching is a problem; this is commonly detected in previous DVAD systems. The detectability of click noises depends on both the spatial resolution of the HRTF and the bandwidth of the source signal. An analysis of the excitation patterns of the synthesized binaural signals revealed that click noises are more detectable when a narrower-band source signal is used; this indicates that higher HRTF with higher spatial resolution is necessary for presenting various real-world sound sources.