Helicopter design is all about inverted progress,the newer the helicopter the more noisy it is.
That's for true, but for the B412!!
110 db in the flight deck for almost ten years; only a Gentex HGU-84 + CEP and modified earcups & earseals could cope.
And still I feel some small degree of acufene (tinnitus) in my left ear when controllers voice raises a bit in the comm.