Re: perceptual segregation of sound

[Brian Gygi <bgygi@xxxxxxxxx>]

There was a lengthy discussion of this topic a while back on the 
auditory list (do a search in the Auditory list archives for 2004 under 
"How many sourcs can humans perceive").  One of the interesting findings 
that was brought up was a statement by Walter Murch, a well-known film 
sound designer (Apocalype Now and others) who developed a "rule of 
2.5".  If there are two concurrent sound sources in a movie scene, it is 
necessary to sync up the sound for each of them, but if there are three, 
it is not.  The problem is, this is a very difficult thing to test. It 
is hard to say if the auditory system is attending simultaneously to 
more than one source, or rapidly shifting attention between sources. 
Experiments that would rigorously test this are quite hard to design.

Brian Gygi
Acoustics Research Institute
Vienna, Austria