Those are 1/3 the design for the Open Baffle Line Array scalable speaker idea in work.
The main two way OB line array will be planar magnetic drivers that work down to the servo sub upper end.
Working with a local person to just assemble the pieces I have for the baffle and then put a finish on it.
After building the flat packs, then put a finish on the 6x12" servo sub H-Frames before driver install and stacking.
The dspMusik 8 channel DSP crossover will let me test ideas with these I have not seen done for other speakers.
Time to have some speaker fun. Been thinking about this since 1979 and now the systems I want are available.