Turns out I already had a “Storm Whistle” among my rafting stuff.
The Storm whistle manufacturer claims that a strongly blown Storm Whistle makes 118-120 dBA in a “soundproof room.”
https://www.stormwhistles.com/frequently-asked-questionsWhen I blow the Storm whistle by mouth directly into the tiny microphone hole of the iPad Air 2 the NIOSH app reads 98 dBA instantaneously.
To get the maximum output I taped the Storm whistle to the output of a battery powered air blower and the reading on the NIOSH app rose to 102 dBA.
