This rear view shows the rear firing tweeter, an Eminence ASD-1001 compression driver and a Dayton 7" waveguide crossed at 2.7Khz, the 4" X 1.5"long port, and the speaker terminals. I found the rear firing tweeter didn't add much if anything to the sound, and I later removed it.
The Zaph Audio Budget Aluminum MTM.
Passive bi-amping using two Emotiva Audio UPA-2 stereo amps. This system is guarded 24/7 by ninja garden gnomes.