As is pointed out quite well in The Book of Five Rings.

Amos: from explosions and gunfire and helicopters and unmuffled generators and air-compressor-driven power tools and motor pools and too-loud noises in general. And I wear and have worn for years hearing protection when I cut the grass, blow snow, fire guns, use a chainsaw or any other power tool...but by then the damage was done. So I have a constant tinnitus and bilateral hearing loss in the upper registers (above about 4 Khz) and I will be fitted for hearing aids on November 6 at, I believe, 1 p.m. and I will gladly pay to the VA whatever the co-pay is. The full enjoyment of music has been too long absent.