“You have to open a door or window to let the pressure out of the room.”

So if you add up the square footage of the walls, ceiling and floor, what difference would a window ( @9-12 square feet ) make? Maybe the advice was just to remove an entire wall? 😳

I have a custom listening room that is nearly airtight. I understand the post, and when manufacturers with bigger speakers have been setting them up in my room, they often run them at very high levels with the door shut. It can get uncomfortable on the ears. 

I used to listen with the door shut exclusively, but the past year or two I have taken to opening the door. It just seems to be a bit different experience, even though I am not trying to pressurize the room greatly. 

@curiousjim You have a nice system… bought into all the potential “snake oil” add on’s… cabling… isolation..  acoustic treatments etc.., (I did also) yet you don’t understand how a 20 sq ft door can effect the acoustic properties of a room…Interesting. 
@mark200mph People that don’t bother to post their virtual system IMHO lack credibility & should not be throwing stones… again IMHO. 

Who is throwing stones I'm chucking boulders😃

Overall, the room is not pressurized by your speaker.  When the cone moves forward, there is a brief increase in pressure, but when it moves backward, there is a corresponding reduction in overall pressure.  A wave has a portion that has a higher pressure and a corresponding part that has lower pressure than the ambient pressure of the room.  What you are reducing by opening a door or window is the acoustic energy in the room (less is bouncing around and more is escaping).  This will change the sound, and whether that change is good or bad depends on the particular room and system and the volume level the system is playing at.  If you are playing at such a high level that the room is overloading, backing off the volume will do more than opening a door.  In any case, just listen to the result; theory will not accurately predict the result.  

I was present when an industry expert was helping a friend set up one of his listening rooms.  He open and closed doors, moved sound absorption and scattering panels around and listened to the results rather than following any sort of formula/theory.  This room sounded better when the panels at the first reflection points on the side walls were removed, for example.  As for open doors, this room sounded better with the door to the room closed, but with a door to a closet in the room opened (the closet acted as a bass trap).