I can not speak scientifically about what you're asking, but I can theorize. The headphones that I have cover the entire ear and have quite a bit of padding. Si

I can not speak scientifically about what you're asking, but I can theorize. The headphones that I have cover the entire ear and have quite a bit of padding. Simply having them on your head lowers the volume of ambient noise by a pretty good bit. I suspect that the engineers that designed the headphones took the dampening properties of the physical object into account and adjust the out of phase volume to compensate. I haven't felt any kind of discomfort or pain that is typically associated with loud noises. They seal well enough that sometimes I swear I can feel a quick pressure change if I remove the headphones quickly enough. That bit could just be my imagination, though.