This image is a graph of Army research which has shown that detection distance
of combat sounds decreases as hearing loss increases.  For example:

A normal hearing soldier can hear footsteps in leaves at 100 meters whereas a
soldier with >H-2 hearing can detect only at 1 meter.

A normal hearing soldier can hear a rifle bolt closing over 1.000 meters whereas
a soldier with >H-2 hearing cannot detect that sound until 46 meters.

A normal hearing soldier can hear a tank idling at 850 meters whereas a soldier
with H-2 hearing cannot detect that sound until 350 meters and a soldier with
H-3 hearing levels (worse than H-2) cannot detect that sound until 130 meters.