Structure of sounds in the world

[Brian Gygi <bgygi@xxxxxxxxx>]

At 11:33 AM 10/10/2002 +0200, Martin Braun wrote:

> Outside the lab all sound is broad-band noise with varying amounts of
> periodic components. If these are strong enough, we hear pitch, otherwise we
> don't.
>
> It is obvious that complex sound with only unresolved harmonics produces a
> pitch perception. But such sound is non-existent in a natural environment,
> and this pitch percept is weaker and slower than that caused by natural
> sound with resolved harmonics.

There are great oversimplifications of the types of sounds we experience
'outside the lab.'  In everyday listening we encounter sounds  that are
band limited consisting largely of harmonic components (bird calls,
whistles, even the human voice), sounds that are broadband with unresolved
harmonics (wind, thunder, machines that buzz) and everything in
between.  The amazing thing is that the auditory system has a way of
accounting for this huge diversity of sounds.  One study my colleagues and
I did on similarity assessment of environmental sounds suggested the major
acoustic component in our psychological organization of these sounds was
the degree of harmonicity in the sounds.