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Re: 1/f spectra
I don't know the Science paper
you refer to, but there have been a few studies on the spectra on natural
sounds:. The problem is the particular setting or corpus of sounds
surveyed will affect the results.
Hodgson, M. R., Rempel. R.& Kennedy, S. (1997).
“Measurement and prediction of typical speech and backgroundnoise levels
in university classrooms during lectures,” J. Acoust. Soc. Am.
Hoth, D.F. (1941). “Room noise spectra at subscriber’s
telephone locations,” J. Acoust. Soc. Am. 12,
looked at classroom and offices, respectively, and generally found that
the spectrum of summed background sounds rolls off (declines in
amplitude) according to a 1/f function, somewhat similar to pink
However, in Gygi, B., Kidd, G. R. and Watson, C. S.
"Spectral-temporal factors in the identification of natural
sounds", to be published in JASA in Jan/Feb., I summed 100
environmental sounds and found that the long-term spectrum had slightly
less than a 1/f slope, possibly due to the inclusion of a
number of impact sounds that had high frequency transients.
In general, in
Attias, H. & Schreiner, C. E. (1997). “Temporal loworder
statistics of natural sounds”. In Advances in Neural Info Processing
Systems, 9, edited by M. Mozer (MIT Press, Cambridge, MA), pp
the authors examined low-order statistics for speech, environmental
sounds and music gathered from samples on CD sound effects. They
found that the power spectra rolled off according to a modified power
is the amplitude of the spectrum at frequency
ranges from 1.0-2.5, and
specifies the f at which the rolloff begins. The
rolloff value is higher for speech than music or environmental
sounds. Note that the 1/f spectral rolloff mentioned above
is a special case of this general law.
I hope this helps.
At 06:29 PM 11/14/2003 +0000, Jan Schnupp wrote:
I have heard it said on a number of occasions that 1/f spectra are
commonly encountered among natural signals, and one might perhaps
the auditory system to reflect this fact in its design
(perhaps the fact that auditory filters get wider at higher CF and
approximately logarithmically spaced is a simple relfection of the
nature of many sounds?)
However, I don't know ANY literature that discusses this 1/f phenomenon.
seem to remember somebody mentioning at a conference that there is
"classic" Science paper that marks the "discovery of the
If that is the case, I'd love to know the citation for it. Any
references for other (particularly recent!) work relating to 1/f and
role in audition would of course also be very welcome. (Even better
be pdf files of relevant papers, if anyone has any).
Thank you very much in advance for your help,
Dr. Jan Schnupp
University Laboratory of Physiology
Parks Road, Oxford OX1 3PT, UK
Tel: +44-1865-272513 Fax: +44-1865-272469