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?
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.
If you had loudspeakers on the outside of your head, and passive attenuation in your ears, yes that would reduce pressure for you, but everyone else would have experience an increase. But adding more pressure in the cavity of your ear to reduce pressure makes very little sense.
You’re so wrong about this. ANC pretty much eliminates pressure inside the ear canal. That’s how ANC works. No pressure waves, no sound, no damage.
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 🤦🏼♂️
Mine work like this: “Got your nose. Neener neener neener.”
Holy shit, buddy. Yes. We flip a signal 180 degrees out of phase and that added pressure pushes the outside wave down. There is at no point a reduction of pressure in your ear, it’s just more pressure that makes it so you can’t hear the sound you are trying to remove. The perception of sound and air pressure are not the same thing.
Bro. It’s not “just more pressure.” It’s literally less pressure.
If there are water waves moving a boat up and down, and you actively apply some movement (ha! pressure!) to the water so you generate waves that cancel the existing ones so that the boat stands still, would you say “but you don’t understand, the boat is getting MORE PRESSURE!!! It’s being damaged!!!”? Of course not. It’s pretty much the same principle.
Get a highschool physics book, read the chapter about sound, and come back. Otherwise, just stop.