The room is rectangular with door a opening to another room but the door was closed while the test was running
That's similar to mine and I don't think the room is the reason for the phase reversal thing. On another note, if you have REW you will see that it makes a significant difference between door open and close. As such, I use my HT with the door open 95% of the time so I ran it with the door open.
The difference is so different as shown on the graphs that I don't even bother to try and hear the difference.
