My husband used to have to wear big earphones at his job. This was to prevent hearing loss because the job he was doing all day involved very loud noises.
I had always heard that if you were exposed to loud enough sounds, it could result in hearing problems. However, I had no idea that the hearing loss was due to the destruction of a tiny hair, on a tiny cell. That's so weird! I also didn't know that you could lose hearing for some frequencies but keep hearing for others.
Luckily my husband's earphones worked great. I put them on once, and couldn't hear a thing going on around me!