What Is The Function Of Hearing Protection Devices?

[Markglance]

Hello friends, Actually I heared from people about hearing protection devices. I want to know how hearing protection devices work? How these devices prevent our ears from noise? If anyone know please anwer this question, I really want to know.

[rccatnap]

They're normally required for people who work in a noisy environment.
My other half worked on the ground at Heathrow Airport for many years as an aircraft dispatcher and he was supplied with a stehoscope-like ear defender, only the little rubber cones did not have a hole in them. They protected his eardrums from excessive noise but allowed conversation to be heard from a person nearby. Some units are frequency specific and they do work to protect your hearing in later life. The Health and Safety Executive published this a few years ago: https://www.hse.gov.uk/research/rrpdf/rr720.pdf
I hope this answers your question.

[rccatnap]

"stethoscope".

[davebro]

OK - but what about noise CANCELLING headphones. How do they work & when using them do you actually get silence or some form of white noise? Just asking.

[rccatnap]

davebro the noise cancelling headphones are specifically for listening to a sound (usually music) of your choosing and there is a built-in sensor that picks up the external noise and replays it out of phase. thereby suppressing it, leaving the music clearer to hear.
It doesn't cancel the extraneous noise completely, but it does a pretty good job.

[Old_Geezer]

I suspect it's more a case of converting it to anti-phase (up-side-down waveform) and playing it at the same time the original sound arrives, so the two cancel each other out. Would need to be fast at converting and accurately timing the play though.