Not actually that brutal at all, I thought it would be interesting to compare KEF's excellent LS50 passive model to their LS50 'wireless' active version.
The measuring microphone position was in the MLP ( main listening position ) and was not moved. Each loudspeaker was measured at 50cm from the rear wall 100cm from the rear wall and 150cm from the rear wall,each speaker at least one metre from the side walls.
Above are the measurement plots for the LS50 passive, green is 150cm or 'free space'
magenta is 100cm away and blue 50cm away from the rear wall.
Above the LS50 active verion, in the same three distances from rear wall, blue is 50cm,
red is one metre and green 15cm or 'free space'.
Below I have overlaid the active and passive versions measured at 150cm away from rear wall,
LS50 active is in red, passive is green trace
Below active is in red, passive in blue measured at 50cm away from rear wall
The measurement plots at 150cm away from the rear wall are certainly the tidiest, as you can see the FR of both the active and passive versions are pretty similar.
I can send the original REW mdat files to anyone just contact me through the Purité Audio site.