ported sub box question???

Hi tw i have a 12inch sub in a ported box in my dc it's weird when i open the passenger door it gets louder i have the box behind the passenger seat. So my question is where should i put it for the max air to get into the box.

 

It's always going to have more power with the extra available airspace when you open the door. Wherever you put it, you'll get about the same performance as long as you're not cramming it under seats or placing the subs face down. Put it somewhere where it can breath the most

 

What sub/box do you have? Pic's?