A fundamental study on the sound pressure level that best matches with the visually perceived distance from the virtual sound source

In order to make a highly realistic audio-visual virtual space, we have studied how to control the sound pressure level of a virtual sound source. According to our prior experiment, it has been confirmed that sense of distance strongly depends on the sound pressure level rather than modification of the frequency response of the sound, at least in the semi-anechoic space. Therefore, we have investigated the sound pressure level that best matches with the visually perceived distance of the virtual sound source, using the method of limits. Additionally, since how the reverberation characteristics of the virtual space look may affect the sound pressure level that best matches with the visual perception, the background image of the virtual space was also altered in the experiment. As a result, we found that a sound pressure level smaller than theoretical one best matches with the visually perceived distance of the sound source.