At 16.28 15/06/2006, you wrote:
>Dear Nature-recordists,
>
>I'm struggling to find software that will produce a clear sonogram for
>analysis and presenting bird calls. I appreciate that the clarity of the
>sonogram is affected by the quality of the recording, but it seems that ev=
en
>with very clear recordings, it is not so easy to produce a clear sonograms
>without excessive "noise"?
often the most disturbing components of spectrograms are the
background noise, the reverberation, and other songs in the background.
many published spectrograms are too clean to be true... most are
completely redrawn by hand!!
I don't like them. I prefer to see more details with a range of gray
levels that indicate a range of dB values.
Often I also tolerate to see some background noise just to understand
the relationships among the signal and the environment in which it is
to be heard.
to get a very clean spectrogram you must have an excellent recording,
but you can also play with the level threshold and the plotted
dynamic range to get high contrast spectrograms.
a different way is to plot the spectrogram (on the screen) with a
full gray range and then copy the image in a graphic editor to
manipulate the gray levels.
try with SeaWave, a freeware software available at
http://www.nauta-rcs.it/SEA/seawave_index.html (you must write to
to get the download path).
I'm sorry the display is not completely compatible with XP and thus
you'll see buttons and controls with different background grays... be
patient, version 2 is on the road!
in SeaWave you can choose among three gray scales, and also you can
shift them up and down to get darker/lighter spectrograms.
let me know if you need help.
Gianni
>Are Kay Sono-graph sonograms (from a prohibitively expensive machine) that
>one sees in publications artificially clean?
>
>Which programs can one use to get clear sonograms? I've tried Raven and
>syrinx-pc but I can't seem to get them even vaguely clear.
>
>Any advice?
>
>Many thanks,
>Callan
>
>____________________________________________________
>Callan Cohen Percy FitzPatrick Institute
><callan%40birdingafrica.com> of
>African Ornithology,
>Mobile: +27 83 256 0491 University of Cape Town,
>Tel/fax: +27 21 685 4081 South Africa.
>Skype: callancohen
--------------------------------------------------------------
Gianni Pavan
Email
Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
Universita' degli Studi di Pavia
Via Taramelli 24, 27100 PAVIA, ITALIA
Tel +39-0382-987874
Fax +39-02-700-32921
Web http://www.unipv.it/cibra
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