Adequate Sound Levels for Acoustic Signs for the Visually Impaired in the Sound Environment with Advertising Sounds on the Street

Abstract

The adequate sound levels for acoustic signs for the visually impaired under the sound environment with advertising sounds on the street were measured through a psycoacoustic experiment to reveal the effect of the advertising sounds such as the ambient music from shop, advertising announcement, and so on. The participants were asked to adjust the playback level of the each acoustic sign to an adequate level by using the fader of the sound mixer while comparing to the background sound levels. The experimental results showed that the estimated adequate sound level for the acoustic traffic signal was approximately 21 dB higher than the environmental sound level, while that for the guidance chime was approximately 17 dB higher than the environmental sound level. The results also revealed that the difference between the estimated adequate level and the environmental sound level were higher in contrast to the sound environmental condition that was mainly comprised of road traffic noise. These results suggest that the consideration under the varied sound environment are required in time of designing the acoustic signs for the visually impaired.