@larryi , the AMT 1B’s had a single driver on the face facet with a matched diameter passive on the back...
If the bass seemed out of phase, it really was the room.
I had an early version of an octave eq that came with a dinky but calibrated mic.
And the means to DSP the space with white noise that likely made the neighbors think our vacuum cleaner had been plugged into the wrong plug....
The issue with AMT drivers ’in general’, imho, is matching the response speed of the bass drivers to keep up. My approach is to have a ’mid/high’ 6.5" bass unit(s) and dump the low bass into a healthy sub or 4.....
Like the ’look’ of the Line 10’s over the Cinnamons’......the latter would be a tough sell to the sig other....