Not meant to be pedantic, just playing devil's advocate, but isn't the real time audio bitstream just a continuous source of events that gets blended with the rest of the application state like active filters and what not?
Even higher level objects, such as what are various called "clips" or "regions" or "events" frequently pay no role in any type of event notification system. In some designs, the boundaries of such objects may play a somewhat event-like fole.