Gopi--
There's some very compelling, collective wisdom in the suggestions
you've received thus far.
(1) Use Line Input on the recorder.
(2) Use Mics with width bandwidth, wide pick-up (omnis) (For very low
budget DIY, search "Panasonic wm-61A DIY")
(3) Also use direct contact sensors (the ground is the primary
membrane/medium, isn't it?)
Are you trying to determine where the elephants are relative to the
mics or primarily capture the low Hz events?
If the location of the sound source is important, I'd consider using
a 4 channel recorder withat least two buried contact mics (Mikes
Rooke's would be great for this, but they're expensive) and one or
two very low-noise, very flat response omni mics like AT4022's. I'd
spread all mics at least 50 feet apart. 200' might be better. Three
mics of the same type, in a equilateral triangle would probably
provide you the timing differences you'd need for locating the sound
source. I'm not sure what 4 mic combination to recommend,.. 3 in the
ground and 1 in the air? Also be prepared for 2 + 2 or 3 in air and
one in the ground? Maybe make one excursion with DIY solutions and a
4 channel recorder to see what's most promising?
Probably beyond your budget, but here's a quality solution you can work-from:
1 - R4 Edirol Recorder ($900)
http://www.proaudiosolutions.com/ProductDetails.asp?ProductCode=EDIROL-R4
Use line-in with the following:
1 - RME QuadMic Preamp ($550) (You might get by with a stereo pre,
but a very low noise one would be more expensive, so you may as well
be equipped for 4 channels)
http://www.bhphotovideo.com/c/product/358454-REG/RME_QUAD_QuadMic_Preamp.html
(I think Eric and Robb are probably right about avoiding the mic
inputs of hand-held recorders)
1-4 AT4022 mics (~270 each)
http://www.bhphotovideo.com/c/product/574512-REG/Audio_Technica_AT4022_AT4022_Small_Diaphragm_Omnidirectional_Condenser.html
1-4 Mike Rooke's contact Mics or Robb Nichols contact Mics or
Richard's design.
http://www.megalithia.com/sounds/tech/piezo/opamp.html How best to
"settle" the contact mics into the ground is interesting to think
about.
Rob D.
= = =
At 8:19 AM -0500 2/11/10, Flawn Williams wrote:
>
>
>The folks at Cornell University have done a substantial amount of work
>recording elephants, and have put a lot of information about their
>recordings on the web. Google on 'Cornell record elephant' and you'll
>find them.
>
>They have used and recommend Earthworks QTC-1 mikes into a Sound
>Devices MP-2 preamplifier and then into a recorder at line level.
>That's a bit beyond your budget, but a good reference point.
>
>You can contact them at: info"at"elephantlisteningproject.org
>
>(substitute @ for "at")
>
>They've done interesting things earlier in the decade with little home-
>brew Windows computers powered by a marine battery called "autonomous
>record units", but these days many of the smaller digital recorders
>could handle the recording chore if driven at line level as noted by
>previous posters.
>
>When trying to record deep into the infrasound, bear in mind that
>you'll need effective shockmounting to avoid structure-borne vibration
>and windscreening to avoid even the slightest turbulence in the air.
>It's definitely best if done with you many feet from the microphone!
>
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