Subject: Re: 1/f spectra From: David Mountain <dcm(at)BU.EDU> Date: Fri, 14 Nov 2003 20:18:23 -0500Background 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(at)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(at)physiol.ox.ac.uk >