Re: 1/f spectra

[David Mountain <dcm@xxxxxx>]

Background noise in natural environments has a roughly 1/f spectrum at low
frequencies but tends to flatten out in the mid to high frequency range.
In our experience the slope is often steeper than 1/f. There are some
background noise data in the book "Sensory Ecology: How Organisms Acquire
and Respond to Information" by David B. Dusenbery Publisher: W H Freeman &
Co.; (1992) ISBN: 0716723336. A similar situation exists in deep water if
rain and wind are not a major issue.  See: Principles of Underwater Sound
by Robert J. Urick Publisher: Peninsula Pub; (1996) ISBN: 0932146627

Most animal communication sounds are most definitely not 1/f.

--------------------------------------------------------------------

David C. Mountain, Ph.D.
Professor of Biomedical Engineering
Boston University
44 Cummington St.
Boston, MA 02215

Email:   dcm@bu.edu
Website: http://earlab.bu.edu/dcm/
Phone:   (617) 353-4343
FAX:     (617) 353-6766
Office:  ERB 413

On Fri, 14 Nov 2003, Jan Schnupp wrote:

> Dear List,
>
> I have heard it said on a number of occasions that 1/f spectra are very
> commonly encountered among natural signals, and one might perhaps expect
> the auditory system to reflect this fact in its design
> (perhaps the fact that auditory filters get wider at higher CF and are
> approximately logarithmically spaced is a simple relfection of the 1/f
> nature of many sounds?)
> However, I don't know ANY literature that discusses this 1/f phenomenon. I
> seem to remember somebody mentioning at a conference that there is a
> "classic" Science paper that marks the "discovery of the 1/f phenomenon".
> If that is the case, I'd love to know the citation for it. Any other
> references for other (particularly recent!) work relating to 1/f and it's
> role in audition would of course also be very welcome. (Even better would
> be pdf files of relevant papers, if anyone has any).
>
> Thank you very much in advance for your help,
>
> Jan Schnupp
> Dr. Jan Schnupp
> University Laboratory of Physiology
> Parks Road, Oxford OX1 3PT, UK
> Tel: +44-1865-272513  Fax: +44-1865-272469
> E-mail: jan.schnupp@physiol.ox.ac.uk
>