Hello All! Here's a copy of an email Dr. Rex Cocroft sent me awhile
back;
Dear Christian,
Thanks for your message. I'm sorry for the delay in responding, but
your e-mail came while I was on a field trip in Mexico and it somehow
slipped through the cracks when I returned.�
It doesn't take that much in the way of equipment to record the plant-
borne vibrations of insects (though it can take a lot of patience!).
An old ceramic phono cartridge works really well (and has a much
higher output level than more recent cartridge designs), in
combination with a pre-amp of the kind you can get in any music
store. Another possibility is to use a guitar pickup as a transducer;
some come on a clip and can be clipped onto a plant stem. This won't
be quite as sensitive as the phono pickup but will still work pretty
well.
To position the phono cartridge, just make sure the needle (that
transfers the vibration through an arm to the ceramic element inside)
is in light but steady contact with the leaf or stem. Run the output
through the preamp to a speaker, computer sound card, video camera
sound jack, etc. One often has to do a certain amount of 'acoustic
prospecting' to get a good recording; some plants won't have insects
on them, don't transmit the vibrations well, or are large enough that
only faint signals are coming through from a more distant location.
Best of luck with your work!
Rex Cocroft
I will also try to post a file Dr. Cocroft attached explaining some
of his work. Hope this helps, Christian Van Horn
--- In "Steve Pelikan"
<> wrote:
>
> Hi all ---
>
> I faintly remember reading an article a while back by an
entomologist
> who recorded the sounds of thrips, mites, and leafhoppers by
attaching
> a phonograph cartridge to a twig on which the bugs were living so
that
> the needle touched the bark and then hooking the thing up to a
recorder.
>
> Perhaps I also read about this sort of thing here, though the
obvious
> searches didn't turn anything up.
>
> Does anyone know of any references to the technique? Or, better, can
> you tell me what circuit to build to connect a phono cartridge to a
> recorder? I'd be happy enough to try it without looking at the
literature.
>
> More generally, I'd be interested in hearing about any small
> transducers or microphones that I could use to record (say)
individual
> bugs walking around. Or worms eating their way through soil, which
is
> my current goal. I've got a worm bin (where we process all our
kitchen
> scraps) to practice on all winter.
>
> NO! It isn't the case that I want to be ready to sell effects (FX?)
to
> the next movie based on Dune!
>
> Sorry for always asking such goofy questions here, and thanks very
> much for any info you can provide!
>
> Steve P
>
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