> My main purpose is to explore possible linkage between geographical variation
> of vocalization parameters of Grey-hooded Warbler (a bird common in
> Himalayan foothills) and ambient noise variation in different habitats.
>
> Many of the sound level meters I have searched on the web give frequency
> range from few hertz to 8000 hertz. The warbler I am studying sings from 2500
> htz to about 9000 htz. I am not competent enough to understand fully the
> implication of using 8000 Htz meter. I guess that the sound meter should have
> freq range exceeding band width of the warbler vocalization. I request for
> comments.
Hi Pratap,
Yes, the sound level meter should theoretically have a frequency range that
fully covers the frequency range of the bird song that you intend to analyze.
However, I would suggest to use the sound level meter only for calibrating your
microphone and the recorder. You could for instance record a 1 kHz test signal
through a cheap speaker and record it at a well-defined distance and then
measure the sound level by using the sound level meter at the same distance.
You would then know the absolute sound level of the recorded 1 kHz test signal
as well as the level of the noise that you record at the same gain setting. In
this case it would be of course sufficient to have a simple sound level meter
with a limited frequency range.
The final noise measurements could then be carried out directly on the recorded
.wav files. This would also allow you to determine the spectral distribution of
the ambient noise, which may also significantly influence the vocalization
parameters of the singing birds. A number of studies have shown that many
animal species shift their songs towards higher frequencies in order to avoid
masking effects by low-frequency ambient noise.
Regards,
Raimund
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