The seeds of the all-enveloping background sound of music in public places that evolved into Muzak were sown in the early decades of the twentieth century. By the 1950s, the concept had developed into a commercial reality that invaded the American way of life, its presence only increasing as the century wore on. The trademarked name "Muzak" has become generic, referring not only to that company's own proprietary mix of piped-in background music, but to any such music in public spaces and the workplace. It is sometimes called "wallpaper" or "elevator" music—a mild pejorative that distinguishes its contrived and synthetic quality from "real" music, listened to actively and intentionally—and signifies its role as ambient sound to be experienced subliminally.

The aesthetic concept of music as an environmental component rather than an artistic abstraction of sound important for its content was consciously advanced in the first decades...