Hi Laura,
Nice to hear from you! Vicki is probably right because it is so pronounced,=
but I have seen a similar effect using manual recording where strong signa=
ls are involved - like from a shotgun or parabola. You could try reducing t=
he contrast and/or brightness settings for the sonogram and see if the back=
ground emerges.
Not that I understand it, because I don't!
John Crockett
Westminster, Vermont
--- In vickipowys <> wrote:
>
> Hi Laura,
>
> Welcome to the group!
>
> I think you had the Automatic Gain Control turned ON, for your
> recorder. For nature recording you should always use Manual Gain,
> set it at a fixed level so that the wanted sounds do not clip. Auto
> gain gives a noise pumping effect, every time a bird calls the gain
> quickly goes down, then gradually up again. This is how the Raven
> jpg looks to me.
>
> However there was no sound sample in the Nelson's Sparrow folder, to
> test my theory.
>
> Assuming you are studying different dialects rather than relative
> loudness, your sound files should be useable although there may be
> some clipping at the start of a birdcall, before the auto gain kicks in.
>
> What recorder were you using, and what microphone/s?
>
>
>
> Vicki Powys
> Australia
>
>
>
> On 16/07/2012, at 10:11 AM, laura.hilberg wrote:
>
> > Hi everyone,
> >
> > I haven't posted here before, but I've been following this forum
> > for a few months now. I am finishing up my Master's degree in
> > conservation biology, and my thesis is a dialect study of the
> > Nelson's Sparrow (found on the coast of New England and inland from =
> > North Dakota up through interior Canada).
> >
> > I just returned from my field season, recording sparrows in
> > multiple locations in Maine. I'll be analyzing my recordings using
> > Raven, and one of the first things I noticed when I opened it up
> > was a strange white space underneath the song, which roughly
> > correlates with amplitude and pitch. It looks like a white echo - a =
> > silent space in a background otherwise full of traffic and wind
> > noise. Since I know that the traffic and wind noise didn't
> > disappear, I'm assuming that it is not really there? "I uploaded a
> > picture and sound clip in the "File" section of the Yahoo Group in
> > a folder called "Nelson's Sparrow").
> >
> > The white space is always there to some degree, but it is much more =
> > extreme in the loud songs, in which I can also hear a little bit of =
> > a bubbling sound (hard to describe). My only idea is that my gain
> > was turned up too high and that distorted the sound at times?
> >
> > I realize that I don't have all the right vocabulary or a deep
> > understanding so this might be hard to follow - does anyone have
> > any thoughts or ideas?
> >
> > Thanks,
> > Laura H.
> >
>
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