DISCLAIMER: THIS IS NOT AN ACTUAL AUDIO RECORDING! IT'S A SYNTHESIZATION OF PRESSURE DATA.
Okay, Patrons -- here's something interesting. I wish there was a way I could incorporate images into this post, but I will have to settle for links which, if you click on them -- will show you some figures I think are necessary to explain what you are hearing here.
https://gyazo.com/abffff4a6070426cb92fbc44c6f167f8
Link 1 shows the cover of a NASA technical document: "Sonic Boom Measurements In The Focus Region During The Ascent Of Apollo 17". Were you aware that the U.S. Navy had instrumented ships during the late stage of the Apollo program, downrange during the launch trying to understand the long-distance acoustic signature of the Saturn V moon rocket? I sure wasn't. When I discovered this, of course my first thought as a filmmaker was: "Oh, please tell me there's something juicy in here I can show people." The answer to that is: kind of.
https://gyazo.com/fd6d9dcf891acf6aaa6bd6d8b33ffac2
https://gyazo.com/745f5bc689fd0f682c8369a3cae3b882
This document contained N-wave pressure data, which is not an audio recording. Think something a bit more like a seismograph -- these are pressure measurement rigs using modified condenser microphones as pressure transducers, feeding DC amplifiers and FM data tape recorders. The boom energy is very low frequency (tens of Hz), so the system was optimized for accurate overpressure capture, not for audio. Traces were plotted and summarized in tables and figures.
However, similar in the way that NASA publishes 'sonifications' of space-environment data, such as the "sound" of Jupiter's magnetic field as recorded by Juno, or of the Sun's corona on the Parker solar probe, we can take the data from these ships and convert it into an audio signal.
https://gyazo.com/4668ef32b6af63646d8b29a501a38afd
I've never done anything like this, and I'm just feeling all of this out. Any audio engineers out there: Let me know if I've erred in a major way! I think it turned out pretty great. A clear double-thump, with a third single thump described in the report as a "reflection".