>Thanks Bernie.
>Of course I am disappointed.
>I would have liked to have determined that I found a viable recording
>package for recording infrasound for under $500.00.
>
>I wish I could find a source of accurate infrasound to use as a check
>but all the freq generators I know of don't go there. I guess my
>next stop should be the zoo to visit elephants.
Alternatively, you could do what the US Army did when testing
infrasound to kill off living creatures (aka humans) in the jungles
of Viet Nam in the late 60s. They took a large piece of plastic,
hooked it up to a very large and powerful driver and pulsed it back
and forth at about 7.5Hz. at outrageous amplitudes (about 120dBA, if
you can imagine). Within about 45 seconds, most living organisms w/in
a 3km radius got either very sick or very dead. There was a paper
(now classified) titled Audiogenic Siezure in Rats written about 1968
the set the stage for this stuff. Problem was, that the operators got
sick, too. The researchers figured that 7.5Hz was a freq that could
cause siezure because of phase cancellation in the metabolic rate of
some cell or nerve structures. So our ever-generous govmint shelved
that one. You could resurrect it if lo freq is intriuging and test
the gear that way. I tried it once in my analog synth days. Everyone
in the studio got way sick. But we sure as hell got infrasound.
Bernie
>
>Rich Peet
>
>--- In Wild Sanctuary <>
>wrote:
>> 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:
>> >> >
>> >> >
>> >> >
>> >> >
>> >> >Your use of Yahoo! Groups is subject to
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>> >>
>> >>
>> >> --
>> >
>> >
>> >
>> >To unsubscribe from this group, send an email to:
>> >
>> >
>> >
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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
>
>
>
>To unsubscribe from this group, send an email to:
>
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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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