Lights asked me to check back in here. I just did a quick scan so please ignore if I am repeating or out of context.
I am also interested as to the reasoning behind the Desect t=0.
A desk reflection can be redirected if absorption is impractical. Desktop Reflection Revealed
The 41 Hz hole looks nasty. Try moving that speaker towards/away from the front wall, then the side wall.
See if the frequency changes. If it does, then you have identified SBIR and the culprit wall.