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

@signaforce Glad to hear that!  I was curious a while back and got the REW software and a mic, and in addition, acquired some technical books to help me better understand concepts like decay, sound wave dynamics and resulting things like room nodes, etc.  I've had a lot of fun listening to, and then testing with the software, things like opening/closing blinds/drapes, doors, moving furniture and of course speaker placement.  Most all of it makes a measurable difference with the software.  Not all of Iit made differences I could notice with my own ears, however.  Or if I did, maybe not always positive differences.  But opening the rear doors to my room (which creates a 7-8 foot "hole" in the back or my room) makes an incredible difference, especially in the bass.  And importantly, I understand why that is given my measurements and study.  Good luck!

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😃