The adequate sound levels for acoustic signs for visually impaired in the sound environment with ambient musics from shops

Providing acoustic signs for the visually impaired is one of the most effective ways to support their orientation and mobility. Although the use of such sounds by the visually impaired has been revealed qualitatively, the acoustical properties of ideal sound-designs for them have not known sufficiently, even a basic property such as the sound level of these sounds. On the other hand, the advertising sounds from shops such as ambient music are the one of the typical sounds in the Japanese down town. Although these sounds let them know their surrounding and the direction toward the down town, these sounds disturb their sound information and make difficult their mobility. Our previous studies revealed the adequate sound levels of acoustic signs under the road traffic noise environment. This study discusses the effect of the ambient music from shops on the adequate sound levels of acoustic signs through the psychoacoustical experiment. The results showed that the relative difference between the adequate sound level of acoustic signs and the environmental noise levels are larger than that under the road traffic noise environment. This trend is thought to be attributed to the frequency characteristics of the acoustic signs and the environmental noise.