IMO, fine grain mesh in front of diaphragm (fine cover) will raises the pressure (or vaccuming it depeding polarity of signal) if its venting not enough.
Like you shut a sealed-room door, there's a resistance from the raising room air pressure, near the end of stroke (that time, door close to be closed but still have gap for venting).
The air volume changing is not much (door are multiple few cm along of stroke) in comparision to your room volume.
Because of that, raising of air pressure in room is quite small, but, it acts reinforce to the door.
Smaller the space (room size), the more air raising (same door size).
Diaphragm to fine mesh is quite small. It can alter the sound by raise up air pressure, also dampenning the impulse.
We may all know that lower air pressure ambient will not well in transfer the low freq, it can make a lack of bass as like you listening on a flat flying airplane.
IMO, a best condition for diaphragm to reproduces audio is when pressure is balance both side of driver, and the raise on a side is same as decrease amount on the other side
I believe it's sonic transparent IF the fine mesh stick on ear hole of listener, or, locate some where in front of the ear... not right infront of driver.
