Okay
Makes sense
It’s hard when you have lived with a 73 “ tv
You said you have a 2 pair of 2123H?
So are you planning a vertical arrangement., woofer +2123+Beyma+2123?
That could be interesting
If you are really stuck for room width you could keep the final enclosures narrow (using your 15 inch woofer) like 19 inch wide externally to form a tower. Even stack the 2123’s and the Beyma on top on the woofer box in a narrow array
That way it would be modular
The ports placement is not critical
The other option that “might” work is vent your dual 2123 with a small rear port and run them down much lower at 140 Hz. That would really give you a low distortion mid.
Some Klipsch owners looking to improve have reported excellent results with dual 2123’s.
Two 2123’s in .8 cu ft vented @86 hz will not reach Xmax till 135db (thermal limited at 132 dB 500 Watts 4 ohms)
I imagine it would be very dynamic!
It would be 105 dB sensitivity ref 2.83 v 1 m
The woofer could side mounted like the Allison concept with the enclosure 13 inches wide
The green curve is the ported enclosure dual 2123 (2x 2 in ports 0.4 long)
The yellow curve is the sealed enclosure
The ported enclosure really drives hard down to 86 hz
Passively crossing that over would be a challenge but it’s an option
In fact the 300 hertz crossover passive is not that simple either
Biamp if you can
Food for thought.