At 06:55 PM 3/27/2011 +0000, John Hartog wrote:
>Clipping can look that way on a spectrogram.
What John says about clipping is true, it can cause false harmonics to be
generated and displayed.
First, what you are seeing is NOT an echo unless it is delayed in time and=
not represented higher in frequency graphically as a harmonic is...
A harmonic will be a multiple of frequency and is not delayed in time.
After years of studying sound pressure waves graphically displayed and
wildlife sounds, I can tell you many birds have a "voice" very rich in
harmonics to some degree, corvids in particular are a classic example of
this. If you measure the frequency carefully of each component in the
spectrogram, you will find a harmonic at 2 times the basic sound frequency=
and another that is usually more pronounced at three times the basic
frequency as third harmonics are always stronger. Very often, what you are=
seeing is coming from the bird, it is not a malfunction or clipping and is=
at a lesser sound level than the primary frequency or sound.
Often this harmonic is what adds brilliance to a birds sound as you hear it=
by ear... So don't disregard it as an undesirable part of the spectrogram=
display, there is a good chance it is real...
Hope this helps...
--
Thanks,
Mitch & Shadow...
Photograpy & Recordings: http://www.4shared.com/dir/UTASxktL/wildlife.html
Shadow's area: http://www.4shared.com/dir/ecfWjyZb/Shadow.html
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