Room interection totally affect the bass, how to get rid of that?

did you try putting up 45 degree panels on the side walls and the wall in front of you?
7ft wall gets about 7 inches of panel.

it can help with the peaks & notches in the room, but even then.. the best way to get rid of peaks or dips is to use an equalizer.. except when using those panels, you might not need to adjust for peaks & dips as much.

i figure the sound goes from cubed to trapezoid.