Set those A-20 aside! Absolutely no passive protection and the active element will not handle the S92. I used the A20 before I was issued a company headset many years ago and I could feel the mechanism jumping about inside.
You need to do research into a headset that can offer as much passive protection as possible. But from personal experience the problem isn’t the ‘noise’ but the shockwave that the advancing blade sends into the right side of the aircraft and cockpit. I would recommend a helmet but I understand that this can be financially restrictive for some people. Try and limit the noise entering the ear and the shockwave resonating through the skill bone. My 10 cents worth.
LZ