The subjective evaluation of the sound environment of urban areas has been widely investigated in laboratories using various acoustic simulation methods. However, visual stimuli, such as videos of the original measurement environment, can also be considered to influence the sound evaluation. This paper proposes a system for the simulation of the target audiovisual environment using headphones and a head-mounted display. The inclusion of the head-mounted display provides insight into the influence of the provision of a realistic panoramic video of the target visual environment on the subjective evaluation. To provide realistic sound environments, variation in the direction of incidence of the sound caused by the rotation of the subject's head is taken into consideration in the proposed system by dynamically updating the simulated direction of incidence using sound data recorded with a six-channel directional microphone, head-related transfer functions, and the angular data of the orientation of the head obtained by a gyro sensor installed in the head-mounted display. To validate the basic performance of the proposed sound simulation system, a subjective sound localization test was performed, and it was confirmed that appropriate sound localization performance can be achieved with the system when the subjects can freely rotate their heads. With the proposed system, a subjective evaluation experiment targeting urban sound environments was performed, and the effect of the visual stimulus on the evaluated loudness and annoyance of the sound was assessed. The evaluation scores of the loudness and annoyance of the sounds were significantly lower when panoramic videos of the original measurement locations were presented to the subjects than when videos of an anechoic chamber were presented. This suggests that the subjective evaluation of the environmental sounds without any visual information concerning the environments give a bias to the evaluated results.
- Dynamic binaural simulation
- Head-mounted display
- Head-related transfer function
- Subjective evaluation