Yes I have already found the 192khz sample rate of my FR2 useful in
recording freetailed bats.
Microphones that don't have specs beyond 20khz, still have sensitivity
beyond that frequency. It's just skewed. But definitely useful.
Certainly when you are dealing with the animal kingdom, and creatures
that use sound outside of our hearing range, the higher sampling rates
are very useful for audio capture.
Danny
--- In Gianni Pavan <> wrote:
>
> Hi all,
> I'd like to underline that recording at 96 kHz may provide
> benefits even if our hears can't hear so high.
> - recordings can be used for scientific uses, not only for listening
> - if you need to measure the time of arrival of an acoustic event on
> two microphones, a doubled sampling rate means double accuracy
> - some species produce high frequency sound (insects, for example) or
> sound with many harmonics extending beyond 20 kHz. In particular when
> recording at short distances.
> - in case of impulsive sounds, such as stridulation, a higher sample
> rate means much better description of the pulses
> - a higher sample rate means more accuracy that could be useful in
> any post processing
> - many recorders and sound boards have poor anti-aliasing filters. a
> higher sample rate is less likely to cause aliasing problems; if any
> aliasing problem occurs, it happens at higher frequencies where it is
> less disturbing
> - most condenser microphones have frequency response well beyond 20
> kHz; with some equalization it is possible to restore high
> frequencies attenuated by the falling response of the mic.
> - in measuring environmental noise high frequencies are extremely
> important. when conducting behavioural experiments in laboratories it
> is very important to monitor any high frequency that could come from
> electronic equipment (TVs, monitors, switching poer units, etc.).
> - some years ago I participated to studies on monkeys where the
> animals were trained to react to specific sounds. but when testing
> them with 44.1kHz recordings the animals did not react. then we
> switched to 96 kHz and the animals reacted with the same frequency as
> with "live" natural sounds. Of course we are not monkeys, but many
> acoustic events have high frequency components that are relevant for
> their accurate identification and description.
> - recording live music made with traditional acoustic instruments, 96
> kHz recordings are much better than at 44.1.
>
> In the case of my Sennheiser K6/ME66 running on the internal battery
> the noise increase begins at 10kHz. I wrote to sennheiser and I'm
> waiting for a reply.
>
> Gianni
>
>
> At 11.57 22/03/2007, you wrote:
>
> >Steve, you wrote:
> >
> > > So here's the question --- what microphones are people using
with the
> > > fancy machines that digitize at 96 and 192 KHz?
> >
> >In my opinion, normal audio recording at 96 or even 192 kHz does not
> >make much sense. It's just some kind of an esoteric or "homeopathic"
> >approach, which might work if one believes in it ;-). As far as I
> >know, there is still no proof that we can hear anything above 20 kHz.
> >The only argument that I would accept is that the anti-aliasing
> >filters in the 96 or 192 kHz sampling mode do not need to be very
> >sharp. A more relaxed (or a higher frequency cutoff) filter will
> >introduce less ringing and phase distortions at the upper frequency
> >limit of our hearing range.
> >
> > > I understand that there are several (very expensive) measurement
> > > microphones that cover the larger frequency range but the ones I've
> > > seen, together with things like the Earthworks microphones, have a
> > > fairly high noise level. (22 - 28 dB A or higher).
> >
> >Yes, it seems to be impossible to design a microphone that provides
> >both a low inherent noise floor and a large bandwidth from 50 Hz up to
> >50 kHz and beyond.
> >
> > > When I visit web pages of manufacturers and view spec's for all the
> > > usual devices people talk about here --- none of them say how the
> > > microphones work in the 25+KHz range.
> >
> >I know of two microphones that try to adapt the 96/192 recording mode:
> >Sennheiser MKH800 and Schoeps MK 21H + CMC 6:
>
><http://www.schoeps.de/E-2004/specs-mk-ccm21h.html>http://www.schoeps.de/E=
-2004/specs-mk-ccm21h.html
> >
> >Both models achieve the extended frequency range simply by boosting
> >the higher frequencies. However, due to physical constraints, the
> >noise floor at the very high frequencies above about 30...40 kHz will
> >also be increased. Therefore, the manufacturers do not specify the
> >poor noise figures at those high frequencies...
> >
> >If you are interested in recording ultrasounds for more scientific
> >purposes (e.g. for bats, rodents or bush crickets), then you should
> >have a look at microphones or bat detectors that have been optimized
> >for that purpose. Avisoft Bioacoustics for instance offers two
solutions:
> >
> >a) Phantom-powered ultrasound microphones for common 96/192 kHz
recorders:
>
><http://www.avisoft.com/usg/microphonesP48.htm>http://www.avisoft.com/usg/=
microphonesP48.htm
> >
> >b) Dedicated laptop (or UMPC [=3D ultra mobile PC]) based recording
system:
>
><http://www.avisoft.com/usg/usg116-200.htm>http://www.avisoft.com/usg/usg1=
16-200.htm
> >
> >Regards,
> >Raimund
> >
> >
> >
> >No virus found in this incoming message.
> >Checked by AVG Free Edition.
> >Version: 7.5.446 / Virus Database: 268.18.16/729 - Release Date:
> >21/03/2007 7.52
>
>
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----------------------------
> Gianni Pavan
> Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
> Universita' degli Studi di Pavia, Via Taramelli 24, 27100 PAVIA, ITALIA
> Phone +39-0382-987874 Fax +39-02-700-32921
> Email
> Web http://www.unipv.it/cibra
>
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> CIBRA organizes the XXI IBAC Congress, Pavia, 15-18 September 2007
> http://www.unipv.it/cibra/xxi_ibac.html
>
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>
>
>
> ----------
>
>
>
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