Hello!
Do not really know where to step out in this community, but I feel of all communities I know this would probably be the most viable one to try my steps.
I am in a profession where I use a 20 ton stamping CNC machine to make sheet metal into various shapes for my company that then bends them into shape for their customer. We are offered ear guards, naturally. And they have active noise cancelling. Though, for me, it's not good enough. I rarely use it to be frank, and instead just removes them whenever I am having a conversation. It's not much we can do about it looking to my company, as they believe they have done what they need to do. But I have a sneaky feeling I can possibly do something myself!
So, current ear guards have a pair of microphones (possibly unidirectional) positioned at the front of each side. It then has a knob that from what I understand has a potentiometer that goes to a amplifier that amplifies microphone to the internal speakers. Just typing this out makes it sound dumb and silly! I have tried my luck, noticed that you can overclock a raspberry to achieve low latency audio. But I really do not understand all this. To start, I think you'd want dual microphones, and have a extra in the back. Maybe even a third sticking right out I would not know. And analyse it with math and algorithms to achieve a better noise cancelling than a single would do. After that, maybe even pattern recognition by sensing that "his" is really, flipping loud! [this] just won't stop sounding (ie constant beep or whatever). And [this] actually was just registered a second ago for the tenth time in a row (bangs from the machine). Don't know if any of that would be possible, maybe I am just reaching for air here and the only thing possible is to go analogue and achieve a somewhat better noise cancelling with extra microphones. I have read, and read, and read. And I know it's at least a very challenging thing. Though it would be really cool, and earphones aren't really that hard to hack fortunately. I do plan, for instance, to add a small bluetooth media card to it one day and change it's batteries to micro USB rechargeable lithium batteries. That I can manage, this is just over my head really!
