Mate this happens to me every single time and its basically why I haven't slept properly since 2019.
You're stood there in a dusty room in Durham thinking you heard nothing, then you get home, stick the headphones on, and suddenly there's this low murmuring that definitely wasn't the boiler. The room was silent. I was there. I know what I heard (nothing) and yet the recorder disagreed quite strongly.
My mate reckons its just pareidolia working on audio rather than visuals but honestly that explanation feels a bit too convenient when the "random noise" is saying something that sounds suspiciously like your name.
Does anyone else find the recordings catch things in a completely different frequency range to what your ears picked up at the time? I'm only a beginner with this stuff so genuinely curious if theres a technical reason or if we're just supposed to accept that recorders are better at communicating with whatever's out there than actual living humans are.