I was actually wondering about this recently and I started thinking about how loud of sounds people working on the deck of an aircraft carrier would be exposed to. I found this interesting article about improving the hearing protection for them, because it turns out even for people who actually use both forms like they are supposed to (most of the people in the jobs exposed to the loudest sounds do, it would likely still be at the pain level for them if they only wore one so they have good motivation) it still isn’t enough for a full workday of exposure.

Here’s the link: https://apps.dtic.mil/sti/pdfs/ADA455113.pdf. The exposure is something like 145-155 dB. They say a final checker will get to the safe limit in only a few takeoffs, and that assumes that they can recover in a below 84 dB environment when they aren’t working, which apparently also doesn’t happen. It seems like it isn’t really a solved problem of how to protect people being exposed to this kind of sound level.

Couple years ago, I visited a historic grand prix that featured classic F1 cars. They also had open pits, so you could walk up and ask questions and literally stand next to the cars.

I was standing next to a 70’s F1 car when they performed an engine test. I was wearing thick, professional earplugs and the biggest Peltors you’ve ever seen. When they fired that thing up, I lasted all of five seconds before I walked out. At that point, it was no longer sound but sheer pressure. You could feel it in your chest.

As for how the mechanics do it? Easy, they’re all deaf as a post. Even the best earpro can’t prevent that kind of hearing damage, especially if that’s your chosen career. If you’re worried about good earpro not being enough, best advice is to put distance between you and the object/career path involved.

There was that Nathan For You episode where they locked that kid in a coffin and had an orgy outside to test the sound proofing. No real practical use but apparently it did a good job.

All jokes aside, I'm very interested to hear if something exists to that degree of practical hearing protection. Maybe a "suit"of sorts to cancel noise and dampen bone conduction or super active noise cancelling?

I did some research about this for myself, the best I could find is an advertised -45dB (Remote Audio HN-7506), which makes me very skeptical, I couldn't find any third party measurements but multiple reviews I read mention that they have about the same isolation as Etymotic earphones.

Active noise canceling is good but only for lower frequencies, it does almost nothing to mid and high frequencies, which is not necessarily a bad thing since mid and higher frequencies are easier to attenuate passively.

The best noise canceling headphones have an average noise cancellation of -27dB (-20dB in the bass frequencies), but the best noise cancellation that I could find (other than the HN-7506 that I don't really trust) is from Etymotic earphones, they are completely passive and have an average attenuation of -32dB with -21dB reduction in the bass frequencies which is really impressive, they work so well because they are inserted much deeper in the ear which can be a bit uncomfortable. I read a lot of experiences from musicians and apparently if you use foam tips instead of the stock ones you can get even better isolation and slightly better comfort.

Another option is custom molded IEMs or earplugs, I couldn't find measurements for those but based on comments from people that have them they seem to have slightly less isolation that Etymotic earphones but they're are obviously infinitely more comfortable since they're custom molded to your ears (there are also soft wraps that increase isolation but I don't know how effective they are).

So if you want the best noise cancellation I recommend the Etymotic ER4XR or the Etymotic ER2XR (afaik most Etymotic earphones have the same body (so same isolation), choose them based on the sound signature you prefer), if you want good balance between noise cancellation and comfort get custom molded earplugs or IEMs.

My sources:

Headphones with best ANC measurements, Etymotic measurements (click on Isolation on the sidebar)

I think we need to define “hearing protection”, and how far your willing to go

For example this is probably less than practical.

It should be noted that active noise canceling doesn’t actually protect your ears. It’s just pumping more noise into them (noise that happened to be exactly opposite in phase, but the pressure is still there.)

The cone of silence obvi

I don't exactly know whether this strat is redundant or not but I wear noise cancelling earbuds with full earmuffs overtop and it seems to do a good job. Plus i get the added benefit of being able to listen to music and hear phonecalls while on a machine.

Offline open source AI pointed me to this article on Wikipedia:

Electronic hearing protection devices

Some HPDs reduce the sound reaching the eardrum through a combination of electronic and structural components. Electronic HPDs are available in both earmuff and custom earplug styles. Electronic microphones, circuitry, and receivers perform active noise reduction, also known as noise-cancelling, in which a signal that is 180-degrees out-of-phase of the noise is presented, which in theory cancels the noise.[1]

https://en.m.wikipedia.org/wiki/Hearing_protection_device