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According to the YT comments, the audio on the video was nicked from here:
soundcloud.com/andreas-bick/dispersion-in-ice-sheet
Actually recorded with a hydrophone under ice on a lake near Berlin.
( , Wed 17 Feb 2021, 0:54, Reply)
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My convolution reverb thanks you.
( , Wed 17 Feb 2021, 15:21, Reply)