Acoustic Comfort in Multi-group Conversation Space: a Field Experiment in an Actual Cafe with Different BGM Levels

摘要

We refer to "Multi-group conversation space (MGCS)" as a space where more than one groups share a space and make conversations within the groups, such as restaurant or cafe. In this study, we investigated acoustic comfort in MGCS considering speech intelligibility and speech privacy as major factors by conducting acoustic measurements and a questionnaire survey to the customers for four days in an actual cafe. The volume of background music (BGM) during operating hours was changed each day at three levels of low, middle and high and no BGM. The indoor noise levels were measured at six representative points with six sound level meters hung from the ceiling. The questionnaire consisted of eight items including ease of making conversation, comfort, and atmosphere (lively/relaxed). The customers were asked to answer questions at their table after having their meal or drink and, at the same time, the occupancy of neighboring table and the number of customers in the cafe were recorded. Results show that the ease of conversation tended to be evaluated better when the volume setting of the BGM was middle level than other settings. Also the impression evaluation varied by gender, age, or seat position and occupancy.