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From: Jim Nollman <>
Date: Mon, 05 Jan 2004 12:32:11 -0800
 Regarding the recent post about digital audio recording, I beg to differ
 with the assessment given.
 Just about every professional sound device being released by the music
 hardware industry these days has a working sample rate of 96 kHz. I just
 bought a Digi002 rack from Digidesign which is a rack-mount portable device
 that attaches to any computer running protools by firewire. It has multiple
 ins and outs and some very sophisticated internal hardware for D/A and A/D
 conversion. Because of the Apple open spec called coreaudio, you can use it
 with just about any piece of new audio software. It comes bundled with
 Protools which is the recording software of choice for just about everybody
 in film and music. I use it a lot out on the water on a powerbook making
 ample use of their high end noise reduction unit called DINR which gives me
 512 bands of mapped EQ control   to notch out any or all or even no part of
 water current, boat noise, or anything else that mars the recording but
 which appears in  a different frequency band then the whales.  Sometimes I
 use it in tandem with my Tascam DAT machine although that is severely
 showing its age with a 48 kHz sample rate.
 I'd avoid the NI card, if at all possible, and absolutely if you are not a
 programmer, because it won't work with anything but their own proprietary
 software which you then have to program to use. But I'm not officially a
 scientist so I don't need the kind of calibration it offers. On the other
 hand, I don't think digital recording software, with its bits and bytes,
 actually needs that kind of calibration any more, although, of course, the
 hydrophone and the specialized wide band preamp still do, although NI can't
 help you there. Much of the issue is not calibration, but something much
 simpler called zero gain. You can  read about it in just about any book
 about recording. In fact, anyone getting involved  in field recording ought
 to read at least one text about the basics of recording.
 I also notice  the advent of a brand new generation of portable professional
 hard drive recorders mostly used by the film industry with effective sample
 rates of 196 kHz and even higher, so you can record frequencies up to nearly
 100 khz. These units range in price with some units going for about $2500.
 I also believe there's a lot better hassle-free, ergonomically designed
 stuff than Ishmael available for a nominal fee on the internet. However, I
 just know the mac stuff and Amadeus is one of the best for the money. The
 old but wise PRAAT has some phonetics graphs that might really surprise
 anyone doing cetacean call analysis. For those wishing more sophisticated
 graphing tools, our group has been happy using Matlab to generate wavelets
 of several cetacean species. You can see some of the results in a gallery at
 on 12/29/03 10:31 AM, Dave Mellinger at [EMAIL PROTECTED]
 > Yes, the mic/line-in port on most sound cards has a maximum sampling rate
 > of 48 kHz, so the maximum frequency it can capture is half that or less.
 > Typically you see good frequency response up to 20-22 kHz.
 > To get higher frequencies, you need a more specialized data acquisition
 > card.  I've used National Instruments cards with success, specifically the
 > DAQCard 6062-E, which is a PC card (PCMCIA card), and the PC6071-E, which
 > is a PCI board.  These should give you single-channel input at the
 > frequencies you need.
 > You may also want to try out Ishmael, which can record sound onto disk
 > according to a schedule you set up, display real-time spectrograms, detect
 > calls, localize calls, and a host of other tasks.  It can interface to the
 > above NI cards as well as some other cards.  It's freely available at
 > <a  href=""; 
 > rel="nofollow"></a> .
         Best Regards,
                                     Jim Nollman
         Interspecies Inc.
         <<a  href=""; 

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