I have now done some messurement.
with the phase 0 on the sub (purple only olympica 3)
https://www.bildtagg.se/file/225lv0y2dtfr7n77menfk7p
RT60 phase 0 on the sub
https://www.bildtagg.se/file/rne6omfkkv7w72sgva9y2zn
Waterfall phase 0 on the sub
https://www.bildtagg.se/file/9mcks6v9n1tpor6r3yudcbs
with the phase 180 on the sub (purple only olympica 3)
https://www.bildtagg.se/file/jxg35tcf7li3a9j4dnvkaq84
RT60 phase 180 on the sub
https://www.bildtagg.se/file/i1jzvrg6wcqeew30320i40qw
Waterfall phase 180 on the sub
https://www.bildtagg.se/file/6wu4sy384wenv3bh7okqn8p
would it help to add bass traps to take the edge of 40hz? And i where would i place them, in the sub corner or/and the oppisite?
what more tings do i need?