--- In Rob Danielson <> wrote:
> I like the suggestion of tying to also make a record of the stimuli
> that _could be_ triggering behaviors-- not relying on dB meters etc
> which most of the studies seem to do,.. Moving the understandings
> forward might require some new techniques-- especially outside of
> labs as Travis seems committed to.
>
> Using multiple channels and somehow placing mics so they obtain the
> aural perspective of the birds might be more necessary in loud
> settings, but using a rig in both loud and quiet settings that is
> optimized to record ambience accurately might provide a more
> measurable sense of relative levels, sound source tonalities and
> space/directionality compared to using "close-up" measure/arrays.
> We've all noticed, many times, how parabolas and shotguns alter the
> impression of the background sounds. Of course, one can make mental
> note these discrepancies in the field, but the info does not get
> embedded in the scientific record like it could with a rig designed
> for ambience. The dynamics of directional mics are quite dependent
> upon aiming and the direction that the critter happens to be calling.
> If I was trying to determine how loud a caller was calling to
> overcome other (background) sounds, I'd much rather have an ambient
> recording to work with.
>
> One of the questions in my mind is whether very good binaural gear
> might be a good way to go. I can almost always detect qualities using
> good headphones that analysis software and great monitor speakers are
> blind to. Rob D.
Hi Rob,
Such kind of research on sound propagation and the influence of noise has a=
lready been done:
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3D2216701
http://www.scielo.br/scielo.php?pid=3DS0001-37652004000200011&script=3Dsci_=
arttext
I believe that simple binaural or stereo techniques, which are being used b=
y amateur recordists are not appropriate for this kind of research. Instead=
one has to design the experimental setup very carefully in order to get me=
aningful and repeatable results, which is essential in a scientific study.=
Close-up recordings are in any case required for measuring the alterations =
of the individual animal vocalizations. The equipment for this task must be=
as simple as possible and the inherent noise level of the recording equipm=
ent is not important here. Instead, one should take care that the recorded =
sounds are not affected by unwanted environmental influences such as reverb=
eration or other disturbing sounds. These effects are a much more relevant =
than the minor influence of the microphone or preamplifier noise levels.
Regards,
Raimund
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