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People often debate the use of mono or stereo microphones inside a parabolic dish. This I have already mentioned here.
In summary: some prefer a mono recording for a “clean” use with spectrogram analysis, others prefer to obtain a stereo recording to have a pleasant soundscape. However, a stereo recording does not exclude the possibility of being able to use only one channel of the two to still obtain a good spectrogram.
Personally, I have always thought that the best thing would be to have both opportunities.
This is why I thought of designing and manufacturing (for my personal use)
a Mono/Stereo microphone baffle to be inserted in a parabolic dish, which gives the possibility to separatly connect one of the two configurations when using a two-channel recorder, or both configurations at the same time if using a mixer/recorder with at least three channels.
I confess that multichannel recording is a world for me that I recently entered, started using a Sound Devices Mixpre-3ii mixer-recorder, then buying an old Sound Devices 302 mixer to be combined with one of my own portable recorders.

Above the project drawing of the baffle and below the realization of the microphone assembly.
Stereo capsules L-R; M = mono capsule facing towards the inside of the dish.

I asked about adding the two signals Mono+Stereo to Jules Ryckebusch who replied:

“The signals are adding. So that gives you, in theory 2X signal that works out to 6dB. It’s what people do when putting four mics in an array too. The correlated signal adds 6db and the uncorrelated noise only adds 3dB so there is an improvement in signal to noise ratio”.

Here a quick audio test using a metronome

below European robins at dawn (mono + stereo – Sound Devices 302 mixer + Tascam DR05X)


  1. Is there a reason why you choose for 3000Hz ie baffle 11,5cm? All above is recorded in stereo and all below is recorded in “mono” because the frequency goes around the baffle.

  2. Two questions: Do you need a mid-side to stereo convertor? Has somebody tried 2 mono capsules parallel and L+R out of phase as figure 8 side mic?

    • Yes, I know using for some capsules it is possible 2 mono capsules parallel and L+R out of phase, but with those I use it is’nt possible.
      For the stereo converter, it depends: if I use a Zoom F8 or another similar recorder I use Rode’s VXLR+ converter to feed the capsules while the recorder is setted to Mid Side recording mode.

    • Peter,
      this is not a Mid Side configuration, although it may seem at first glance, so it does not require a Mid Side decoding.
      Could we consider this type of configuration a sort of Mid Side without the possibility of adjusting the stereo width? It may be…

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