In Audacity (which is free), if you go to the Analyze menu and choose plot
spectrum, you get a frequency histogram for all the frequencies allowing you
to easily identify peak frequencies.
Chris Harrison
San Antonio, TX
From:
On Behalf Of Peter Shute
Sent: Wednesday, November 21, 2012 2:30 PM
To:
Subject: RE: [Nature Recordists] Re: Determining peak frequencies
Yes, there's a spectrum option in Audacity's Analysis menu. I think Sonic
Visualiser also does it, perhaps even live as you play the track?
Playing with it, if I was trying to use it to determine either the highest
or the loudest frequency in a call, I'd be wondering what I should set the
"size" parameter to. Its value has a dramatic effect on the resulting graph.
I'm under the impression that a large value makes the graph more accurate
for low frequencies, and a low value is best for high frequencies. So if I
was trying to determine the highest frequency, I should set it to a low
value? But how low? Doesn't it depend on how high that frequency is?
Obviously I don't know what that frequency is yet, so how do I know what to
set it to? Similar problem for the highest frequency.
What does one do? In practice, is there a FFT window size setting that
everyone uses to determine these things?
And for the highest frequency, how does one distinguish the call from mic
hiss, etc?
Peter Shute
> -----Original Message-----
> From:
<naturerecordists%40yahoogroups.com>
>
<naturerecordists%40yahoogroups.com> ] On Behalf Of Avocet
> Sent: Thursday, 22 November 2012 2:49 AM
> To:
<naturerecordists%40yahoogroups.com>
> Subject: Re: [Nature Recordists] Re: Determining peak frequencies
>
>
>
> > 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.
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