I have an infallible micro leak detector .. she's called Andrea and is 11 years old ...
Compared to me she can hear the grass grow!!
(25+ years of being an avid target shooter does not improve your hearing, even if you are very careful!)
To be sure, a set of good enclosed headphones, and a small amplified microphone would work, but i mostly just go get Andrea, or my Peltor electronic Earmuffs, and crank the volume right up, but they are not very good direction indicators.
"Sapere Aude"... Dare to KNOW!
The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...
103% of all people do not understand statistics...
Do not adjust our mind, theres a fault in reality :-)