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Re: Infrasounds recording with SL, Colour Direction Finder, Bat DownConverter r-t

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  • dariusjack2006
    Thanks Wolf, I mean your prerecorded bats voices in attached audio file, using electret microphone. Can bats ultrasound voices be recorded live and
    Message 1 of 9 , Apr 10 7:20 AM
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      Thanks Wolf,

      I mean your prerecorded bats voices in attached audio file, using electret microphone.

      Can bats ultrasound voices be recorded live and downconverted to audio
      in real time to be heard via soundcard ?

      I need upconversion in case of infrasounds to work alike.

      --
      3 mics configuration
      http://soundsorange.net/images_extra/tetrahedral_array2.jpg

      2/3 microphones configuration was mentioned by
      Markus Vester, DF6NM in his manual to work for Colour Direction Finder.

      How to contact Marcus via this group or email to discuss details?


      Please leave my topic "as-is" since I really need to know "all-in-one"

      (amended to soundcards)



      --- In SpectrumLabUsers@yahoogroups.com, wolf_dl4yhf <dl4yhf@...> wrote:
      >
      > Hello Darius,
      >
      > I am not aware of sample recordings being made with stereo microphones.
      > Possibly my Zoom H1 would be up to the job (its sampling rate is just
      > large enough to catch the lowest frequencies of the local bat
      > population, but lacks sensivity). But I am not sure about its
      > directional pattern, I wouldn't expect much from it (at least not enough
      > for acuoustic 'radio location' / direction finding).
      > The human ear performs a much more complex 'analog signal processing'
      > than the radio direction finding for the 'two crossed loop' configuration.
      >
      > About batch-driven image post-processing : Never heard of it. Maybe
      > GIMP does, but I never tried.
      > For a fixed image size of the waterfall (saved by SL), you can use the
      > 'fixed window size' option. It's described somewhere in the manual, but
      > I'm too lazy to look it up myself at the moment.
      >
      > All the best,
      > Wolf .
      >
      >
      > Am 09.04.2013 15:18, schrieb dariusjack2006:
      > >
      > > Hi,
      > >
      > > Let me first congratulate Wolfgang for great success of his excellent
      > > Spectrum Lab.
      > > Number of options is so great, left-side buttons can be right-mouse
      > > click scripted and configured, user's configurations can be scripted
      > > via REAME_configuration.txt, so it takes me a lot of time to test and
      > > master SL (not Second Life).
      > >
      > > So just few questions.
      > >
      > > 1.
      > > Tested yesterday Bat Converter to work for a pre-recorded audio file.
      > > Tell if alike filter can be developed to work for infrasounds,
      > > converting the infrasound up to audio (real-time) and if Bat Converter
      > > or such Infrasound Converter can work on-line getting live input from
      > > the environment.
      > > http://www.qsl.net/dl4yhf/spectra1.html
      > >
      > > 2.
      > > Radar functionality, meteor observations, Doppler shift recording,
      > > live analysis to get speed and direction for tracking of meteors.
      > >
      > > Markus Vester, DF6NM mentioned a use of 2/3 microphones to test his
      > > Colour Direction Finder.
      > > Is available test audio file or can one be generated (binaural
      > > frequencies)to get ColourDF functionality to work in test mode ?
      > >
      > > My laptop comes with built-in mic (mono mode) so I plan to use 2
      > > external mics (one connected for lef and other for right channel
      > > stereo input)
      > > and have a speaker moving in a space to see Direction Finder or 2D
      > > tracking to work.
      > >
      > > 3.I would like to process waterfall output images in another application.
      > > Is it possible to preset size of output image file in pixels
      > > if yes, how ( via configurations ?)
      > >
      > > thanks
      > > Darius
      > >
      > >
      >
    • wolf_dl4yhf
      Hi Darius, ... Yes, that s what the bat converter configuration is for (Quick settings .. Natural radio / animal voices .. Bat Converter). It uses the
      Message 2 of 9 , Apr 10 12:42 PM
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        Hi Darius,


        Am 10.04.2013 16:20, schrieb dariusjack2006:
         

        Thanks Wolf,

        I mean your prerecorded bats voices in attached audio file, using electret microphone.

        Can bats ultrasound voices be recorded live and downconverted to audio
        in real time to be heard via soundcard ?

        Yes, that's what the 'bat converter' configuration is for (Quick settings .. Natural radio / animal voices .. Bat Converter).
        It uses the FFT-based audio filter to shift high frequencies into the audio range (something like 40 kHz down). The opposite (move a band of frequencies up) is also possible to make infrasounds audible without time compression or expansion.

        Of course you need a soundcard with 96 kHz or better 192 kHz sampling rate for it, as recently mentioned here.
        Beware of some crappy cards out there which claim 96 kHz sampling rate but with internal low-pass filters cutting off anything above 20 kHz.

        All the best,
          Wolf .

      • Dave
        ... Another approach would be to hetrodyne the band of interest down to audio frequencies, and then use SL to analyze that. Here s a bit of information on
        Message 3 of 9 , Apr 11 8:21 AM
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          --- In SpectrumLabUsers@yahoogroups.com, wolf_dl4yhf <dl4yhf@...> wrote:
          >
          > Hi Darius,
          >
          > Am 10.04.2013 16:20, schrieb dariusjack2006:
          > >
          > > Thanks Wolf,
          > >
          > > I mean your prerecorded bats voices in attached audio file, using
          > > electret microphone.
          > >
          > > Can bats ultrasound voices be recorded live and downconverted to audio
          > > in real time to be heard via soundcard ?
          > >
          > Yes, that's what the 'bat converter' configuration is for (Quick
          > settings .. Natural radio / animal voices .. Bat Converter).
          > It uses the FFT-based audio filter to shift high frequencies into the
          > audio range (something like 40 kHz down). The opposite (move a band of
          > frequencies up) is also possible to make infrasounds audible without
          > time compression or expansion.
          >
          > Of course you need a soundcard with 96 kHz or better 192 kHz sampling
          > rate for it, as recently mentioned here.
          > Beware of some crappy cards out there which claim 96 kHz sampling rate
          > but with internal low-pass filters cutting off anything above 20 kHz.

          Another approach would be to hetrodyne the band of interest down to
          audio frequencies, and then use SL to analyze that.

          Here's a bit of information on ultrasonics:

          http://www.midnightscience.com/ultrasonics.html

          (I've met Phil, but I have no connection with the site/company.)

          > All the best,
          > Wolf .

          Dave
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