David Brinicombe [naturerecordists] wrote:
> Peter Shute [naturerecordists] writes:
>
>> I listened to Ruffed Grouse on this recording:
>> http://www.xeno-canto.org/153365
>>
>> I don't know how that recording compares to yours, but I can hear it
>> ok on my PC speakers, which have cones about 5cm diameter, but much
>> better on my MDR-7506 headphones, which have 4cm drivers.
>
> Peter,
>
> There weren't any details about how this was recorded, but the grouse
> stands out distinct from the general soundscape, probably very close
> to the mics. The spectrum peaks above the other sounds at +30 from
> 5Hz to 170Hz, well into woofer range.
>
>> On a side note, the Xeno Canto spectrogram doesn't really do the
>> drumming justice, showing it as insignificant dots at the bottom of
>> the scale, and doesn't even show the end of the sequence. I wish
>> they'd show live spectrograms as you play the recordings.
>
> The spectogram doesn't match up, full stop.
>
> From the download, The waveform shows a single pulse with a half
> wavelength of 8.6ms corresponding to a frequency of around 58Hz - not
> good on laptop speakers. I would have expected to hear some reverb or
> harmonics. but it is a single clean pulse. Is there any other bird
> which emits a single frequency call without harmonics? On a power
> spectrum of the whole recording, the frequency range of the LF call,
> 30dB higher than the peaks of all of the rest of the power spectrum,
> spans 5Hz to 170Hz between the +30 peaks. At 300 Hz, it plunges to
> noise levels at 44dB below peak at 300Hz. This bird is putting out an
> extremely "harmonically clean" call.
>
> I'd love to hear Jennifer's recording.
The "drumming" of the Ruffed Grouse is not a vocal call at all, but is prod=
uced
by beating of the bird's wings. It might not be expected to have a typical=
"vocal" overtone spectrum?
John
---
John E. Burchard, Ph.D.
Tepe Gawra Salukis
http://saluqi.home.netcom.com/
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