I was curious to see if it might be related to something called Schumann resonances since there are three harmonics that fall in to the range of human hearing a

I was curious to see if it might be related to something called Schumann resonances since there are three harmonics that fall in to the range of human hearing at 20.8, 27.3 and 33.8 Hz [1]. I doubt that it would ever be strong enough to be perceived by the human ear but if the ionosphere can act as a wave-guide at those frequencies (20 and 40 Hz) then a fairly distant but loud noise could conceivably 'bounce' the sound hundreds or thousands of miles and 'hearing' it would depend on a) being at the exact location that the sound wave bounced down, b) ideal atmospheric conditions, c) being able to hear low frequency sounds and or d) having something inside a house that develops a sympathetic resonance. Slightly plausible but highly unlikely but it did lead me to https://en.wikipedia.org/wiki/List_of_unexplained_sounds https://en.wikipedia.org/wiki/List_of_unexplained_sounds which made the thought experiment worthwhile. [1] https://en.wikipedia.org/wiki/Schumann_resonances https://en.wikipedia.org/wiki/Schumann_resonances