Thanks Mark/Chris/Walter for all the hydrophone info - that's great.
I'll let you know how I get on. And if I discover any monsters of the deep :)
Julie
--- In Walter Knapp <> wrote:
> From: julie freeman <>
>
> >
> > Hello,
> >
> > I'm looking to record some underwater and underground sounds from a
> > fishery in Bedfordshire, UK.
> >
> > On a limited budget I have found these hydrophones that I thinnk will
> > do the job adequately:
> >
> > http://www.dolphinear.com/pro/pro-specs.htm
> >
> > Frequency Response (Overall): 15 Hz - 20,000 Hz +/- 3db
> > Hydrophone Transducer Type: MPC (Piezo) High output
> > Configuration: OmniDirectional, BALANCED OUTPUT, 600 ohms XLR
> > Hydrophone Packaging: Rugged epoxy case, 60mm Dia x 8 mm Thick
> > Cable Type: High Quality, Low Noise, Neoprene/PVC jacket for long life
> > Cable Length: 10 metres (standard); special orders to 100m lengths.
> > Output Connector: Standard 3 pin XLR
> > Power: NONE, does NOT require phantom power - compatible with equipment
> > that provides up to 48v of phantom power on the balanced leads.
>
> The Dolphinear I tried was the regular, not the new pro. And some time
> back now so it may have been a earlier model.
>
> It's problem was the shielding was not good enough. It would pick up
> local radio stations anytime I tried to use it. From the moment it
> entered the water. With nearly a pound of magnetic chokes on it I could
> make out other things but not completely eliminate the radio stations. I
> was using it in fresh water.
>
> I contacted the company and they admitted that they'd had some problems
> with it picking up ships radio on the ocean. They are the ones that
> suggested the magnetic chokes.
>
> You'd want to make sure that problem was fixed or else avoid the Dolphinear.
>
> I replaced it, with the similar Aquarian hydrophone system (gotten used
> off ebay)
> http://www.aquarianaudio.com/products.htm
> This does not have the radio pickup problem. It's a ok hydrophone.
>
> Recently I acquired a Cetacian Research C13 hydrophone. I've not really
> had a chance to give it a good test yet, waiting the gopher frogs
> calling. So far it sounds good.
> http://www.eskimo.com/~cetacean/hpinfo.html
>
> > My question is: I think I will need a pre-amp - what do I look for
> > when purchasing one of these?
>
> Many hydrophones have a built in preamp. Or will work with regular audio
> inputs. I plug the outputs from mine directly into the Portadisc mic
> inputs. Or line inputs if using the headphone out of the earlier ones.
>
> Walt
>
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