Hello Jak
What was that you said?
Speak up lad!
Take the MP3 earphones out and listen to me
Ah!, that's better
Yes, hearing - it can only degrade from birth - like age - it's unlikely to improve
From the RN point - can they expect you to aurally detect a tonal from a Typhoon at 127db, which is abeam your towed array, at 200yds doing 12 kts in the north Atlantic in winter?
Jonesey did it in the 'Hunt for Red October' - but that was against the 'caterpillar' - which I believe, has been removed since the film!
Another good test is - if you whistle a tune and your mates complain - you are probably tone deaf
My last hearing test in the "insulated box" took place when contractors were removing part of the the roof with pneumatic hammers
However, that's a different frequency and db level, so I passed my bit
Best of luck next year