In checking out the ruffed grouse signal, Rich, two things seem to
happen depending on the software one uses. If I use a HAM weighted
low pass filter setting, I certainly get a reading (probably
artifact) from the signal showing it almost down to zero. I doubt
it's THAT low. The wingbeats generate lots of pulsed air and,
depending on the habitat and input transducer, there can be
distortion and other acoustic anomalies introduced. If, on the other
hand, I look at the signal with the GWI system, I don't get much if
any signal below 28.5Hz. That sounds more real to me and I would tend
to trust that analysis as being closer to what's actually happening,
if indeed, it's that low.
Bernie Krause
>64kb spectral display:
>http://home.comcast.net/~richpeet/grouse.jpg
>
>200 kb wave at:
>http://home.comcast.net/~richpeet/0298.wav
>
>Thanks, I really have these questions because I am not in the audio
>business and am not an expert. I just do what I do.
>
>Rich Peet
>
>--- In Wild Sanctuary <>
>wrote:
>> Send a short .wav file, Rich, and I'll check it out, here, on the
>GWI
>> system. Sometimes recordings create an artifact that looks like a
>> sub-harmonic but is really a "ghost" signal created by wierd sums
>and
>> differences.
>>
>> Bernie Krause
>>
>> Wild Sanctuary, Inc.
>> P. O. Box 536
>> Glen Ellen, CA 95442
>> 707-996-6677 tel
>> 707-996-0280 fax
>> http://www.wildsanctuary.com
>>
>> >They speak of calls of 18 hz. I asked and didn't get a response on
>> >if the grouse I recorded with a signature to 1/2 hz was accurate.
>> >I have now asked Adobe if the spectral display is correct.
>> >Maybe they (wcs.org) are speaking of voice calls at 18 hz but if
>so I
>> >don't understand the body mechanics of that. The lowest I have in
>> >voice recorded to date is the Great Gray Owl.
>> >
>> >Rich Peet
>> >
>> >
>> >--- In Doug Von Gausig
><>
>> >wrote:
>> >> See http://wcs.org/7411/?art=3D110481374. Some dinosaur folks are
>> >thinking
>> >> that the subsonic calls of the Cassowary may be very similar and
>> >> pleisiomorphic to the calls that Dinosaurs used to
>communicate...
>> >>
>> >> Doug
>> >> Doug Von Gausig
>> >> Clarkdale, Arizona, USA
>> >> Moderator
>> >> Nature Recordists e-mail group
>> >> http://groups.yahoo.com/group/naturerecordists
>> >
>> >
>> >
>> >To unsubscribe from this group, send an email to:
>> >
>> >
>> >
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>>
>>
>> --
>
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--
Wild Sanctuary, Inc.
P. O. Box 536
Glen Ellen, CA 95442
707-996-6677 tel
707-996-0280 fax
http://www.wildsanctuary.com
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