Real audible sound pressures span a range of one million to one in amplitude

Evidence

The sound pressure for real sound sources can vary from less than 20 micropascals (20 Pa or 20  106 Pa) to greater than 20 pascals (20 Pa). — David Howard, Jamie Angus, coustics and Psychoacoustics, 180

Categorization

• CANDY: A fun elevator fact: the quietest thing you can hear and the loudest thing you can stand differ by a ratio of a million to one.
• XREF: connects to: Human hearing spans a ratio of millions between faintest and painful sound — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 604