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Re: Kayaking with Hydrophones

Subject: Re: Kayaking with Hydrophones
From: "charlieo12345" <>
Date: Mon, 22 Mar 2004 13:49:21 -0000
Bernie,

I am going to use 2 - H2's wired together. Interesting information about th=
e 33 ft
spread. Aquarian suggested that it might be much closer, like 3 ft? His the=
ory was
that if sound travels three time faster in water then in air three times th=
e thickness of
the human head should do it. Sounds like your experience is different. Glad=
 I bought
the 6 meter cable package. I might actually need three kayak with me in the=
 center
with the recording equipment. This could be interesting.

Thanks for the info.

Charlie

--- In  Wild Sanctuary <> wrote:
> Looked at Aquarian's web site, Charlie, but couldn't anything related
> to a stereo unit. Did I miss something? Also, if you're recording
> stereo, optimally we've found that one would need approximately a 10m
> (33ft) spread between transducers to get a spatial effect equivalent
> to the illusion of stereo space one would expect with good
> terrestrial recordings. How, from a kayak (unless you have a floating
> spreader or two kayaks), do you plan on doing this? In our
> experience, because of the density of the medium (water), a spread of
> just a couple of feet won't work too well.
>
> Once, when recording and counting migrating bowhead whales off the N.
> Slope of Alaska and trying to get a handle on the numbers and
> locations, we set up a tetrahedral system. With four hydrophones, we
> located three at 10m apart on the surface on buoys, and one below,
> suspended equidistant from the others, and captured the sound on a
> four-channel recorder. By measuring and charting the slight
> differences in arrival times, we were able to get a 3-D image of what
> was happening under water with bearded seals and the whales. By
> playing back any two channels, the stereo imaging and illusion was
> really pretty awesome which is how we arrived at the 10m formula.
> Less that that, everything sounded more or less like a two-track mono
> recording.
>
> Bernie
>
> Wild Sanctuary, Inc.
> P. O. Box 536
> Glen Ellen, California  95442-0536
> Tel: (707) 996-6677
> Fax: (707) 996-0280
> http://www.wildsanctuary.com
>
> >--- In  Walter Knapp <>
wrote:
> >>  >    From: "charlieo12345" <>
> >>  >
> >>  > I am heading to Baja, sea kayaking with a set of stereo
> >>hydrophones going after
> >some
> >>  > neat sounds. Other then dropping them down over the side anyone hav=
e any
> >specific
> >>  > experience recording that way?
> >>  >
> >>  > Any suggestions to get me started would be appreceated?
> >>
> >>  Check the whole system out before you go. And note how just about
> >>  anything you do will produce noise they record. You'll have to work o=
ut
> >>  how to quiet all that.
> >>
> >>  I'm curious just what stereo hydrophone? I've not seen any adverts fo=
r
> >>  stereo ones.
> >>
> >>  Walt
> >>  
> >
> >Thanks everyone for the great ideas! I enjoy the depth of stereo in my n=
ature
> >recordings so I bought two H2 Hydrophones from "Aquarian Audio Products"=
,
> >http://www.aquarianaudio.com/products.htm
> >Robb there is making me up a special pigtail to connect them to a stereo=
 jack.
> >I'll report back how it works.
> >
> >Charlie
> >
> >
> >
> >"Microphones are not ears,
> >Loudspeakers are not birds,
> >A listening room is not nature."
> >Klas Strandberg
> >Yahoo! Groups Links
> >
> >
> >
> >
>
>
> --



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