Usually listeners pay attention to 1 auditory stream at a time, with that stream or object standing out from the others. Different listeners may latch onto different streams, and in listening multiple times listeners may pay attention to different streams each time. Murch says that hearing can only attend to 1 of 3 sounds presented at a time, so no more than 3 foreground audio streams should occur simulatenously. Otherwise the listener may be unable to separate the streams.
