> “Moreover, despite a number of reports, MacPherson is not convinced the Hum has ever been recorded, even by sophisticated audio equipment.” I found this to b

> “Moreover, despite a number of reports, MacPherson is not convinced the Hum has ever been recorded, even by sophisticated audio equipment.” I found this to be the most relevant part of the article. There was a side investigation into electromagnetic effects but this was disproven with a faraday cage. So... this “mystery” seems to be plain old tinnitus, albeit a low frequency version.