Hello,
took me some time to get back to measuring and fix my levels problem.
So here are my observations :
First comparing L+R without sub (blue) , then L+R+Sub phase 180 as it was set (red) and L+R+S phase inverted (green).
We can see that Mains and sub meet together around 60Hz.
I noticed a big dip with phase 0, just before 90Hz.
080417lrsdiff.jpg
Same one zoomed below 200Hz
080417lrsdiff200.jpg
Waterfall for the sub
080417lrsp+wfl.jpg
My main speakers are supposed to go down 40Hz (that we can see on the first graph) but there was a matching problem with the sub.
After a little searching, i found out that changing the crossover filter on the bass manager from 60 to 120Hz would do the trick !
Sub phase 0 initial (dark green) and with modified crossover (light green)
080417lrsp+c.jpg
Waterfall for the two measures
080417lrsp+c wfl.jpg
So, no eq yet, just trying to optimise with settings changes.
Next i'll see what i can do to work on higher frequencies by changing speakers position.
Regarding EQ, it seems obvious that i need a first filter around 40Hz for the sub.
What do you think ?