Sound travels about 5 x faster in water (approx. 1100ft/sec in air
and 5000 ft/sec in water, depending on salinity and temperature),
Charlie, and has very different transmission properties because of
the density of the medium. Given our experience, my guess is that a
three foot spread ain't gonna work very well. You'll need more.
>Bernie,
>
>I am going to use 2 - H2's wired together. Interesting information
>about the 33 ft
>spread. Aquarian suggested that it might be much closer, like 3 ft?
>His theory was
>that if sound travels three time faster in water then in air three
>times the 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 have 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=
out
>> >> how to quiet all that.
>> >>
>> >> I'm curious just what stereo hydrophone? I've not seen any adverts =
for
>> >> stereo ones.
>> >>
>> >> Walt
>> >>
>> >
>> >Thanks everyone for the great ideas! I enjoy the depth of stereo
>>in my nature
>> >recordings so I bought two H2 Hydrophones from "Aquarian Audio Product=
s",
>> >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
>> >
>> >
>> >
>> >
>>
>>
>> --
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
--
Wild Sanctuary, Inc.
P. O. Box 536
Glen Ellen, California 95442-0536
Tel: (707) 996-6677
Fax: (707) 996-0280
http://www.wildsanctuary.com
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