If I recall correctly the maximum Noise Reduction Rating (NRR) for earplugs and earmuffs is around 30db. You can combine the two for a slight increase in hearing protection but you still hit a limit because of bone vibration.
Is there PPE out there to go even further beyond this? Where would it be commonly used?
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I know nothing about this subject, but my instinct would tell me that anc would actually be protective. If you phase out sound, it
seizesceases to exist, right? That is the whole point of it?Again, pure instincts, don’t know shit myself.
*ceases, FYI (not being snarky, maybe autoincorrect got you on voice to text)
Edit: also “seizes” used here was kinda funny
That’s just not true.
Your ear largely hears things through changes in air pressure. Projecting the same frequency and amplitude at the opposite phase prevents the change in air pressure in the first place. It’s literally cancelling the sound.
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You’re not adding more pressure anywhere; you’re cancelling that pressure out.
Except that’s exactly how nose canceling ear phones work. It’s not like they have an external speaker projecting sound 🤦🏼♂️
This is partially correct, partially wrong.
As many have commented, flipping a signal by 180° cancels it out. However, this is only true for static noise though. Transient noise cannot be canceled out completely, because you would need to see into the future to know which signals to play to cancel out the noise.
The ANC headphones I own mainly cancel noise through passive shielding of the ears. The “active” noise canceling feature is not contributing a lot.