With audio's increasing importance in computer applications, users will soon need presentation, management and organizational capabilities similar to visual window systems to avoid a confusing cacophony of multiple audio sources sounding at once. The ways in which an audio window system could be used are described. These include multimedia documents, spatial data management systems, and teleconferencing. The signal processing methods used to create hierarchical and spatial distribution among nearly arbitrary (not pure sine wave) audio sources are discussed. A prototype system, combining hierarchical and spatial processing functions with a computer-controlled switch, software and human input devices, is presented. Two envisioned implementations, a terminal-based system and a network-based server, are described. Preliminary work suggests that an effective audio window system needs much less complexity and fewer levels of digital signal processing precision than the current prototype.