[AAABEST]

That’s a lot of math. Just go with adjustable noise cancellers AND a pair of foamies.

You can converse perfectly and/or use comms but all loudness is gone.

[LouAvul]

My objective is to come up with a solution that allows me to hear ambient noise. A mountain lion moving through rustling leaves, behind me. For example.

My ear plugs are very efficient and even with high dollar electronic muffs turned all the way up, I still can't hear soft noises. Electronic muffs turned up sans plugs are good, but the NRR is in question. Hence, my OP.