But honestly, if you're at a concert and need to hear a yell, maybe just take one plug out for a sec? Fiddling with folding them seems like a hassle when the music is loud. The whole point is to protect your hearing, not to make it kinda work sometimes. I'd rather miss a few words from my friend than risk permanent damage later.
Just a heads up for @henry_perry16, that folding trick works great with reusable plugs! Foam ones are meant to expand and seal, so folding those might still block too much.