Hi
At such a low frequency, the call will not be in any sense directional,
either from the bird's point of view as an emitter or from your
microphone's point of view. You are not going to miss the signal from
being too close. Most likely, the recording equipment simply cannot
respond enough at such low frequencies to give you any perceptible
signal, or perhaps the amplifier/speaker you used for playback is not
capable of rendering the sound. You should see if you can see the signal
in a sonogram. That would give some clues.
Cheers, Chris.
On 03/18/2013 10:18 PM, Arwen B. Ximenes wrote:
Hi again,
something has been bugging me - I'm not sure if I'm barking up the wrong tree
here, but would distance from the sound source actually be problematic in your
recording? How close were you, Phil?
>From what I can tell from a quick google, the frequency of the sound you
describe is approx 36 Hz, which is very low, just within the lower limit of normal
hearing (of humans) and if the wavelength calculator I have found is correct, then
at a temp of 25C the wavelength would be 9.6 meters. Does anyone know what the
minimum distance (nevermind angle) would be from a cassowary to capture its call?
As I say, I may have got this completely wrong, but you may have been closer,
which might explain why you didn't pick up the soundwave - can someone set me
straight on this one?
Regards,
Arwen
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