PHYSICS AND ASTRONOMY COLLOQUIUM

Thursday, April 19, 2007
4:10 p.m.

1415 Biomedical & Physical Sciences Bldg.

Refreshments at 3:30 pm in Rm. 1400 BPS Bldg


Speaker: William M. Hartmann
         Michigan State University

Title:   Human Auditory Organization and the Perception of Pitch

Abstract:

The auditory systems of humans and other animals must solve the problem of
extracting the sounds of different simultaneous source from the wave
superposition present at the ear.  Obtaining reliable information about the
world by listening depends on solving this multiple source organizational
problem, and we are good at it.  A combination of physiological and psycho-
physical observations indicates that auditory organization, both sequential
and simultaneous, depends on the neural processes that underlie pitch
perception.  They involve place-of-excitation coding, which is (more or
less) preserved in cochlear implants, and synchrony coding which is not.
These processes can be studied with psychoacoustical experiments using
mistuned harmonic detection and unmasking. Both will be demonstrated. 

The colloquium will begin with an (unrelated) demonstration of the
"audio spotlight," which projects audible sound via ultrasonic waves.