as stated by Raimund, 192 kHz sampling board may have limits, though they
can be used in many cases.
a-a filters integrated on good sound boards are not "ideal", as they don't
cut frequencies at 95.9 kHz, though they perform reasonably well by
starting attenuating at, say, 85 kHz, reaching -12 ... - 18d B or more at
the Nyquist frequency and reaching a reasonably complete attenuation at
frequencies of 105 ... 110 kHz. This means that only frequencies in the
range 96 to 110 kHz may happen to fold down - progressively attenuated - in
the range 96 to 82 kHz. Thus the range up to 80 kHz can be safely used and
only components in the range close to nyquist should be examined with
suspect. Often frequencies up to 85-90 kHz can be safely acquired if the
mic itself attenuates higher frequencies.
The LynxTwo, a PCI board, can run up to 200 kHz; its a-a filters are pretty
good and it can be safely used up to 90-92 kHz.
As soon as possible I'll check other 192 kHz devices, including the new
Roland and the Core-Sound mic2496 (despite its name it can be internally
switched to 192 kHz; in this case only the electrical SPDIF can be used to
transfer data to a laptop through the companion PDAudio CF card - please
wait for a complete report!).
Gianni
Gianni
At 10.36 12/05/2004, you wrote:
>One should note, that 192 kHz recording equipment might not be suited for
>recording any sorts of bat echolocation calls. Usually, it is not possible
>to exploit the theoretically possible maximum signal bandwidth of 96 kHz if
>there are any signal components above the 96 kHz limit (the practical limit
>is about 80 kHz). The problem is that the integrated anti-aliasing filters
>do not fully reject sound components slightly above the Nyquist frequency
>(half of the sample rate). Such high-pitched sound components (harmonics of
>bat calls may go up to 200 kHz) would be folded down to lower frequencies
>below 96 kHz. However, most audio microphones have much lower bandwidths
>(they act as an additional anti-aliasing filter), which would prevent such
>potential aliasing problems.
>
>There are special solutions for recording bat calls that use special
>ultrasound microphones and higher sample rates (up to 500 kHz). One of these
>is the UltraSoundGate system. Even if it requires a computer, it is possible
>to prepare a relatively compact unit by using a compact mini notebook PC:
>
>http://www.ultrasoundgate.com/jvcopen.jpg
>http://www.ultrasoundgate.com/jvcclosed.jpg
>
>Regards,
>Raimund
>
>Avisoft Bioacoustics
>http://www.ultrasoundgate.com
--------------------------------------------------------------
Gianni Pavan
Email
Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
Universita' degli Studi di Pavia
Via Taramelli 24, 27100 PAVIA, ITALIA
Tel +39-0382-507874
Fax +39-02-700-32921
Web http://www.unipv.it/cibra
________________________________________________________________________
________________________________________________________________________
>From Tue Mar 8 18:27:12 2005
Message: 1
Date: Tue, 11 May 2004 13:57:54 -0000
From: "Rich Peet" <>
Subject: Re: Nature Recordists Campout #2
Cabin is not full. I may stay there too, if I sleep at all that is.=20
It is $50 for the weekend.
Hope to see you when you can make it.
We need someone who could teach vibrational sound. That would be fun
but I currently don't know anyone with those types of pickup elements.
The main reason we asked for preference on workshops is because if
there is one with no interest we would drop it to make more time for
other stuff.
Don't worry about snoring. Most men do and most of the people comming
are men. Just put tissues in your ears. Bedding is available and
cooking equipment is available. I will bring a grill and it has a
microwave. We just have to go to the grocery store to buy food.
we are staying and editing at the whitetail cabin, see photos at.
http://www.buckeyeview.com/cabins/index.html
--
Rich Peet
--- In "Eric V. Schmidt" <>
wrote:
> Rich;
>
> Hello again. Got ready to send in my monies and am confused.
>
> By the way, I'm the only one coming - my friend had to back out.
>
> Anyhow. If I want to stay in the cabin how much is it. I think
its either
> $50 or not available.
>
> If the cabin is available how much is it? If not I assume it is
$30.
>
> Is this correct?
>
> I am coming, but it looks like I will arrive late. Had a shoot
rescheduled
> for the 21 - so I won't get started until late in the day. And I
can't
> drive a lot at night. I have a tendency to fall asleep - anymore
it is a
> given.
>
> Anyhow let me know.
>
> Eric
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