バックグラウンドミュージック
Background music is commonly played where there is no audience at all, such as empty hallways and restrooms and fitting rooms. It is also used in artificial space, such as music played while on hold during a telephone call, and virtual space, as in the ambient sounds or thematic music in massively multiplayer online role-playing games. It is typically played at low volumes from multiple small speakers distributing the music across broad public spaces. The widespread use of background music in offices, restaurants, and stores began with the founding of Muzak in the 1930s and was characterized by repetition and simple musical arrangements. Its use has grown worldwide and today incorporates the findings of psychological research relating to consumer behavior in retail environments, employee productivity, and workplace satisfaction.