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RE: Use of a laptop / sound card for field recording

Subject: RE: Use of a laptop / sound card for field recording
From: Cetacean Research Technology <>
Date: Fri, 11 Feb 2005 08:43:29 -0800
This information should address both Jim Nollman and Douglas
 Gillespie's comments.
 Douglas makes a very good point in distinguishing between the analog
 response and the digital sample rate.  In fact, some of the
 24-bit/192 kHz stand-alone digital recorders and firewire interfaces
 have an analog frequency response of only 40 kHz.  The Edirol FA101 is
 one example of a computer interface that can sample at 192 kHz but
 which only has an analog bandwidth of 40 kHz.  The Sound Device 722
 and 744 may also be in the same category, but we won't know until they
 are independently tested.  Two months ago, I asked with one of the
 owners of Sound Devices about the frequency response of the 722 and
 744.  He told me that they only have the capability to test up to 40
 kHz, therefore he didn't know what the frequency response of the
 devices will be when sampling at 192 kHz.
 If you're looking for a computer interface with a 24-bit/96 kHz sample
 rate and a 40 kHz bandwidth, the new Edirol UA-25 works well.  I just
 installed one on a hydrophone system for the American Cetacean Society
 and it's been performing quite nicely.
 Regarding Jim's comments, there are devices that record to hard disk.
 Gianni mentioned a few of them.  The Sound Devices 722 and 744
 mentioned above are two and the new Edirol R-4 is another.  The Sound
 Technology ST400 to be release later this year is also a hard disk
 recorder that will be able to withstand much higher shock than pro
 consumer devices like the 722 and R-4.
 Jim's idea about using a PCMCIA interface to a standalone hard drive
 with the Fostex FR-2 was very interesting, so I talked with the
 professional products manager at Fostex.  Unfortunately, his answer
 was that the idea will not work.  However, Fostex does make a
 combination hard disk recorder and DVD RAM recorder called the PD-6.
 It's a six channel device that can record simultaneously to DVD RAM
 and a 40GB hard drive.  It currently only records at 24-bit/96 kHz,
 but the head engineer said the reason for that was the size of the DVD
 RAM when the device was first released.  He believes that it should
 only take a software upgrade to allow the device to record at
 24-bit/192 kHz with an analog bandwidth of 80 kHz.
 Besides memory capacity, there are two other factors that I believe
 are important when considering what type of portable digital recorder
 to use.  The first is the ruggedness of the device.  Hard drives are
 great because they can hold a lot of data.  However, they are
 susceptible to shock and humidity, and you are much more likely to
 lose data when recording to a mechanical medium than to a solid state
 medium such as compact flash.  Therefore, if you think you'll be in
 rough conditions and might bang up your recorder, get the CF recorder
 and spend a bit more on the recording medium.
 The second thing to consider is the overall price of the device.  The
 Fostex FR-2 has a list price of $1499 with a MAP (Minimum Advertised
 Price, that is dictated by the manufacturer) of $1299.  The Sound
 Devices 722 has a MAP of $2375 and I'm not sure what the list price
 is.  The Edirol R-4 has a list price of $1895 and a MAP of $1595.  The
 Fostex PD-6 lists for $9995 and has a MAP of $8500 (this device has
 lots of bells and whistles like two radio microphone outputs, built-in
 mixer, etc.)  High speed 1GB to 2GB Compact Flash cards sell for $100
 to $200 each.
 It should be noted that all of these devices are relatively cheap when
 compared to research grade equipment that are required for most
 research done in the physical sciences.  My biggest caution to anyone
 doing acoustic research is not to be burned by using cheap consumer
 electronics when trying to make high-quality scientific measurements.
 Happy recording,
 Joseph R. Olson
 Cetacean Research Technology
 PO Box 70186
 Seattle, WA  98127
 TEL: 206-297-1310
         877-824-5432 (outside the Seattle local calling area)
 FAX: 206-784-0557
 Mobile: 206-650-8676
 Cetacean Research Technology is a strategic partner of
 Sound Technology, Inc.
 Spectra Group - Signal Analysis Division

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