Effects of sound source and its direction on subjects' impression of soundscape in workplace

In the ordinary workplace, there exist many kinds of sound. However, workers usually do not intend to listen to them. To keep soundscape in workplace good, it is necessary to know how they feel such sound that they take no notice of. In the present research, one experiment was carried out for the purpose. Twenty subjects participated in the experiment and experienced three kinds of sound source, that is conversation, music, and signal sound, that had sound pressure level of 50 or 60 dBA and presented from four different directions. Results show that sound of 50 dBA has generally better impression than 60 dBA and signal sound of each SPL is recognized as bothering and not calm. On the other hand, 50 dBA of conversation and music that are presented from behind worried subjects little. Besides, 60 dBA of music presented from right and left side of subjects is felt as obstructive as the 50 dBA of signal sound. As a result, it is suggested that soundscape in workplace should be planned with attention to the person's behavior, meaning and volume of sound source, and its spatial layout.