Hi Ruediger,
DAT recorders are now obsolete and it is becoming very difficult
to repair them when faulty. The way to go now is solid state
recording. A good DAT alternative solution could be a M-Audio
MicroTrack 2496. It is a compact CompactFlash recorder; this means you
must buy a number of CF memories depending on how many hours you plan
to record before transferring the digital files to a computer for
definitive storage. The cost is around $400 to which you should add
the memories: a 4GB CF now costs less than $100 (you don't need the
fast and expensive CFs for digital cameras) and allows recording more
than 5 hours with DAT quality (two channels, 48 kHz sampling, 16 bit).
If you have one hydrophone only you can record 1 channel wav files to
double the storage duration to about 11 hours; you can also record at
96 kHz to get a frequency range of up to 44 kHz (at the low freq end
the response is -3dB at 8 Hz, thus suitable for large whales!); of
course, the cost of this is halving the storage duration. If more
recording time is needed you can switch to MP3 but you need to
consider the drawbacks. It also allows recording with 24 bits, but
normally you don't need this because the noise of the system
(environment+hydrophone+preamplifier+recorder) may mask the 24 bit
advantages... As with a DAT recorder you need to carefully choose how
to couple your hydrophone to the recorder inputs. As it has internal
not replaceable rechargeable batteries, you should also consider
buying an external battery box with a mini USB connector (you can also
easily build one) to provide additional power in the field.
Advantages vs. DAT: direct copy of wav files to PC, no moving
mechanical parts, no head wear, not sensitive to humidity, no
immediate obsolescence, much more reliable and flexible (1 or 2
channels, up to 96 kHz sampling, linear wav or MP3).
About the M-Audio, I could also say that Nauta-rcs (www.nauta-rcs.it)
has developed a timer board to be installed in the M-Audio (it
replaces the battery and thus you need to provide external power); by
connecting it to a serial port on a PC you can program the recording
schedule.
The only problem of M-Audio is that the P48 powering is not standard
and the microphone preamplifiers are a bit noisy, and thus the unit
may be not suitable for recording very quiet sounds. It's otherwise
certain that the digital input does not perform digital resampling,
and thus you can eventually use it to digitally record from a high
quality mic preamplifier and A/D. This could be, for instance, the
CoreSound Mic2496 or any other A/D you like.
If you can spend more then there are more choices, but nothing special
for less than $1K. If you can wait, there are two new promising
models expected to come out in early 2007 (Fostex and Korg). Another
option is the very new ZOOM H4 recorder, about $300; people recording
music appreciate it, but I've never tested it and thus I can't be sure
it has all the features (quality, usability, reliability) I would
like. For a general overview on solid-state recorders and the hidden
features of digital systems, visit our web pages at
http://www.unipv.it/cibra/edu_equipment_uk.html and
http://www.unipv.it/cibra/res_techtest_uk.html
Gianni
--------------------------------------------------------------
Gianni Pavan
Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
Universita' degli Studi di Pavia
Via Taramelli 24, 27100 PAVIA, ITALIA
Tel +39-0382-987874
Fax +39-02-700-32921
Web http://www.unipv.it/cibra
Email
At 23.56 12/10/2006, you 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
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