Eno's theory of the "discreet music" he called ambient was far from the modern chill-out room: the idea was that it should function at very low volumes, unobtrusively coloring the atmosphere of a room. Evolving by tiny gradations, the long pieces of Music For Airports (the first in a series of albums that followed the statement of purpose Discreet Music) defy close attention, but then they're not meant to be listened to consciously; they're meant to serve as a counterpoint to the frantic arcs of travel, or rather to be imagined in that setting.