ABSTRACT
Physics can tell us the mechanism by which disturbances propagate
through the air. If this is our definition of sound, we have the problem
that in physics there are no limits to the frequencies and levels which
must be considered. Biology can tell that the ear only responds to a
certain range of frequencies provided a threshold level is exceeded. This
is a better definition of sound; reproduction is easier because it is only
necessary to reproduce that range of levels and frequencies which the ear
can detect.
