Sound recognition is a bit like eye sight, some people have more sensitive hearing with better ability to determine/separate differing frequencies. Many are tone deaf. I know in my house I can hear a car door closing out side 90% of the time when no one else can. Also my wife can't tell when a tune is off key.
This you-tube vid was posted elsewhere on forum and some couldn't hear when the AC is flying in formation. I had no such problem. The hole resonance changes when instead of 12 cylinders 24 are vibrating the air and airframe.