Alan, I use Praat (http://www.praat.org), which is an excellent free/open
speech analysis/synthesis program, but can be used for many animal sounds as
well. It can create power spectra. It takes a little while to get used to,
though. Avisoft-SASLab is highly regarded bioacoustics software, and it has a
free "light" version. But I don't know if the light version does power spectra.
Best, Gabriel
--- In "symmerista" <> wrote:
>
> Gabriel,
>
> That makes sense, though I'm not sure why people would use a measure that you
> get from a chart type other than the ones that they provide! Unfortunately,
> while Raven Pro apparently generates power spectra, Raven Lite does not (and
> the price difference is all-important for my students!).
>
> Raven Lite's the only sound analysis software with which I'm familiar; this
> is probably unreasonable, but do you happen to know of any very inexpensive
> software that can generate power spectrum charts?
>
> Thanks,
>
> Alan
>
> --- In "mipartitus" <mipartitus@> wrote:
> >
> > Hi Alan,
> >
> > "Peak frequency" is not a well-defined term, but often this measure is
> > taken from a power spectrum, not a spectrogram. A spectrogram (which you
> > use, and which indeed is more useful for visual identification) is a power
> > density plot as a function of time and frequency. A power spectrum is a
> > power density plot as a function of frequency only. It might well be that
> > in your second example, Arethaea phalangium, the maximum power ("peak
> > frequency") is around 15 kHz. It is hard to tell. I don't use Raven myself,
> > but I am sure it can make power spectra. Look for a plot with frequency on
> > the x-axis and power ("dB") on the y-axis, and determine which frequency
> > the maximum value is at.
> >
> > Best, Gabriel
> >
> >
> > --- In "symmerista" <aharvey@> wrote:
> > >
> > > Greetings,
> > >
> > > My Field Biology class and I have been recording unknown birds and
> > > insects, as well as developing libraries of known local species and
> > > "sound keys" to help them identify their unknowns. We use Raven Lite to
> > > visualize the sound files. For crickets and katydids, we often see "peak
> > > frequencies" in the species descriptions. We were hoping to be able to
> > > use peak frequencies in our keys, but now I'm not so sure that will work.
> > >
> > > For some species, the published peak frequency clearly matches up with
> > > the spectrogram of the corresponding call (e.g., 3.4 kHz in Neoxabea
> > > bipunctata on this page:
> > > www.bio.georgiasouthern.edu/bio-home/harvey/peakfreq.html - I don't yet
> > > know how to post images more directly to the group!).
> > >
> > > In other case, I do not see how the peak frequency was determined. E.g.,
> > > in the second species, Arethaea phalangium, the peak is listed at 15kHz,
> > > but I don't see how you would conclude this from the spectrogram.
> > >
> > > Can anyone provide some insights here?
> > >
> > > Thanks!
> > >
> > > Alan
> > >
> >
>
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