David,
By "peak frequency" the insect folks mean the loudest frequency, I think.
Audacity seems like a worthy alternative to Raven Lite, though it has enough
options to get my students into trouble! Thanks for calling my attention to it.
The power spectrum for Arethaea phalangium does techically show a maximum peak
at 15kHz, but there are several other peaks nearly as high in the 10-15kHz
range, and a few more biggies from 18-20kHz. Not sure how to incorporate that
into our identification guide! But it does make me think that conventional
katydid song descriptions aren't yet optimal.
Cheers,
Alan
--- In "Avocet" <> wrote:
>
> > 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?
>
> Alan,
>
> Audacity - it's free. It does both audiograms and power spectra and is
> worth putting up with a few fiddly wrinkles.
> http://audacity.sourceforge.net
>
> Sorry to be picky over the terminology but "peak frequency" can be
> taken to mean the highest frequency or the frequency at the highest
> level which is really the peak power frequency which can be anywhere
> in the call.
>
> If I have a variable pitch call I would select the peak frequency
> (highest frequency) and plot the power at that frequency on the power
> spectrum. If I want the peak power frequency (over the lenght of a
> call) the power spectrum plotted over the whole call provides this.
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
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