  Re: perceptual segregation of sound  This note was intended to
be sent to the entire list (my change of e-mail address
prevented it from appearing); Dan has replied to me privately.
What you've suggested so succinctly seems a lot like the
concepts on perception that I discuss on my Web site. Using a
basic system analysis approach I've tried to find fundamental
principles from which to establish generalized requirements for
sensory systems based on what it takes for animals to survive in
their environments.  Here is some of my thinking: Survival
requires an animal's sensory organs to produce a timely response
to environmental information. These responses must identify the
relative importance of sources in a way that describes a
"situation" whereby "awareness" characterizes the auditory
scene. In any situation, sensors should be able to select for
attention instantaneously the single most important source
within the scene. To do this the model I propose has a hierarchy
of perceptual levels each of which has