[MARMAM] Recording devices for cetacean vocalizations - FEEDBACK

Ignacio Garcia-Godos ag_godos at yahoo.com
Wed Oct 25 17:25:26 PDT 2006


Dear friends,
   
  Thank you very much to all the people who gave me advise about the recording devices. Here you will find a summarized view of all the suggestions I received.
   
  In general, the recording device you need will depend on the field conditions you work and the complementary equipment you have to work with it.
   
  Many people recommended to use a portable solid-state (no movable parts) recorder M-Audio MicroTrack 24/96 (US$350.00 in Amazon), which use CompactFlash cards (you can find it up to 4MB, US$. 100).  This is a WAV - MP3 two channel recorder, USB powered, with a frequency response from 20Kz to 20Khz, with sampling at 44.1, 48, 88,2 or 96KHz, which will define your band-width response and the duration of the memory card. This would be the ideal portable recorder only if you have a computer in your fieldwork station, so you can download the sounds to the computer’s hard disk and use again the SD card.  But if you want to record many hours you will need more than one card, so, more money.  If a computer is not available, you will need enough cards to store all the sounds you require, so, more and more money.
  I did not found any paper on bio-acoustics that used this device.
  For more information consult this page:
  http://www.m-audio.com/products/en_us/MicroTrack2496-main.html
   
  Other solid state recorders are deck-style hard-disk recorders, large, expensive and not so portable. They have the advantage of a better frequency response (96KHZ) and a large memory in their hard disk (40GB or more), with two or four channels.  But if you have enough money to have this device, better use a laptop with an extra hard-disk.  The price begins at US$ 2650.00 for that used by colleagues in the field.
  You can consult the next link: 
  http://www.sounddevices.com/products/index.html
   
  The cheapest option is a portable Digital Audio Tape (DAT) Recorder.  This older technology, almost obsolete but still in use.  In short, this is a digital CASSETTE recorder.  The very best are the Sony TCD models (between 250 and 500 dollars), with a frequency response of 20Hz to 22KHz, enough for dolphins and some whales.    You can get digital tape to reach 5 hours of recording time. When the hydrophones are connected via a preamp to the line input the recording levels are very acceptable. The preamp is needed to maximize the dynamic range of the DAT recorder.  But remember that many hydrophones come with a build-in pre-amp.  This device comes with an I/O digital slot to move the sounds to a computer, but does not work with a computer.
   
  If you are concerned about its reliability, I found a lot of bio-acoustic papers that had used these portable recorders in the field.  Actually, the SWFSC still use these devices during field-work onboard small boats. A used Sony TCD-D7 or D8 can be found around US$ 300.00.
  These DAT Cassette recorders are ideal if you have not a computer in the field.  So, you can record the sounds in the cassettes and analyze them in your laboratory when you return to civilization.  This is the choice that fits better to researchers from developing countries or with very limited funds like me. 
   
  Laptops are the fancier recorder devices.  You will need an audio card that transforms the analogic signal in a digital one.  You also need a lot of space in your hard-disk.  The advantage is that you can see the sound spectrum in the screen and you can track the sound if you are using a stereo hydrophone having the appropriate computer programs.  The problem is that you have to be sure that your computer will be completely dry onboard, mainly if you work in a small and unstable boat and considering bad weather conditions.
   
  Remember that in field conditions you have to keep dry and secure your devices, so a waterproof case is a good investment.
   
  Well, to all the people who asked for feedback, I hope you find this post helpful.
   
  Regards, 
   
  Ignacio García-Godos N.


Ignacio Garcia-Godos <ag_godos at yahoo.com> wrote:    Dear all,
  I am looking for some advise on the best way to record  cetaceans vocalizations using a hydrophone deployed from a small boat.  I heard that a Digital Audio Tape (DAT)Sony TDC-8 a is a good option for recording many species. This model is not available new at the moment because it is discontinued by Sony, but I could get a used one. Considering DAT technology is almost obsolete right now, maybe you can recommend me any digital recorders or other devices that you use to record cetacean vocalizations on the field. 
  I am specially interested in sounds of blue, sperm, humpback, and killer whales and many dolphin species ocurring off Peru, for this reason I would need a recorder with a wide range of frequencies, from 20Hz to 22000Hz, like the Sony model I mentioned above.
   
  Thanks in advance,
   
  Ignacio
   
   


  Ignacio García-Godos Naveda 
Unidad de Depredadores Superiores 
Instituto del Mar del Perú (IMARPE) 
Esq. Gamarra y Valle s/n, Chucuito, Callao 
PERU 
  Apdo. 22, Callao, PERU
Telf: +511 4297630 Ext. 258 
Fax: +511 4200144 

Casa/Home: 
  Av. Francisco Mariátegui 129 - Dpto. 403, Jesùs María, 
  Lima 11, PERU
  Telf:  +511 4726850 
e-mail: agarcia at imarpe.gob.pe 
           ag_godos at yahoo.com
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