The box is an MTM with 2 A12pWeN in a Woden specified ML-TL. The A7.3eN sits in a near aperiodic midTL out the back. XO is at 250 Hz. We have tried both simple 1st order PLLXO, the active 4th order DSP in chris’s HT, and the passive. All work well.
The passive XO is proprietary, but air coils and proper caps push the parts cost beyond what could be done bi-amping with a PLLXO.
The modeled anechoic response is down to 25 Hz, and the magic of the A7.3eN is improved. The 2 drivers blend really well (better than the, also very good) SDX7/A7.3 WAW.
If one is not worried about using the passive XO the midTweeter can be replaced by the 4” or less FR of your choice. A5.2//3, A7ms, A6.2, will retain the sonic signature.
The speakers in my main system have usually changed regularily, but except for a few changes to do demos, these have remained in the main system since that Sat night in Aug 2018 @ diyFEST.
A number have been built, people are very happy. Plans are available.
dave