And a nice teardown is done here, by the same guy: http://www.righto.com/2015/11/macbook-charger-teardown-surpr...
> Doesn't take "acute," just takes "not destroyed."
It depends. Played in an orchestra, and I've found out that hearing is very different from person to person. Seen people with hearing lower than 20Hz band, or people who can hear a wrong note in a symphony orchestra recording, or people who can perfectly tune their instruments by ear... The list goes on and on.
Our ears' equalizers are not always flat and equal. We can damage them yes, but not everyone starts from the same point.