Hi,
You have already explained that the cutoff frequency between the Neo10 and the servo sub was 180 hz and that between Neo10 and Neo3 was 1800 hz with a low slope.
Can you specify the slope of these cuts?
Have you tried active filtering solutions with lower and steeper slopes?
That's okay. I am not offended by your questions.
I'll show you and everyone the actual and real acoustic slopes and measurements on these.
Now a line source has to be measured and tested quite differently than a point source design. The mic has to be further away and floor and ceiling reflections have to be accounted for. So the measurements have to include an in room response. And the room as to be well treated and well known to not skew the data or cause a misinterpretation of the data.
So the squiggles in the measurements are because of the room reflections. The dead drop at 20kHz is also common with any speaker in this room.
And I have to look at the responses of each speaker in both sides of the room.
Here is the speaker on the left side of the room.

And here is the one on the right.

Note too that the scaling of the graph is a 5db scale. So this is an incredibly smooth response for a room measurement.
So the slope and roll off can be easily seen.
Electronic crossovers really don't apply and can't really be made to work very well with line sources. The reason is that the output of a line source is skewed to the lower end. Lower wavelengths couple and add gain while the upper wavelengths do not. So the crossover is much more than just a crossover. It is a filter designed to make a linear response out of an acoustic response that is not linear. That means the filters is manipulating the response of each group of drivers within their pass band. Textbook filters don't do that.
And most active filters put too much in the signal path that degrades the signal. And you have to deal with yet another power supply, A/C noise levels, more power cables, conditioning.... op amps in the signal path, more connections, additional cables, and on and on...