The Influence of Binaural Room Impulse Responses on Externalization in Virtual Reality Scenarios

A headphone-based virtual sound image can not be perceived as perfectly externalized if the acoustic of the synthesized room does not match that of the real listening environment. This effect has been well explored and is known as the room divergence effect (RDE). The RDE is important for perceived externalization of virtual sounds if listeners are aware of the room-related auditory information provided by the listening environment. In the case of virtual reality (VR) applications, users get a visual impression of the virtual room, but may not be aware of the auditory information of this room. It is unknown whether the acoustic congruence between the synthesized (binaurally rendered) room and the visual-only virtual listening environment is important for externalization. VR-based psychoacoustic experiments were performed and the results reveal that perceived externalization of virtual sounds depends on listeners' expectations of the acoustic of the visual-only virtual room. The virtual sound images can be perceived as externalized, although there is an acoustic divergence between the binaurally synthesized room and the visual-only virtual listening environment. However, the "correct " room information in binaural sounds may lead to degraded externalization if the acoustic properties of the room do not match listeners' expectations.