That's nothing compared to how the room will trash response smoothness.
EQ will address both.
Exactly. Why you would waste power and volume displacement with an isobaric arrangement for a sub is beyond me. Move both drivers out to be able to move air in the room, place, measure, EQ until suitable response found. If not adjust and repeat.
“You are not special. You are not a beautiful and unique snowflake.” Chuck Palahniuk