Eli5: Why do earplugs max out at 33db of noise cancelling?

Question

Eli5: Why do earplugs max out at 33db of noise cancelling?

In: 3288

Answer 1

I asked an Audioligist recently and he said anything more that that is useless because at a certain point the vibrations of your skull will still activate the bones in your ear. We were discussing highway wind noise on a motorcycle and I am heavily paraphrasing.