I just don't get the field coil thing that he's come up with. About the only mentioned parameter improvements he mentioned were high BL and lower flux modulation. But the drawbacks are substantial: high cost, a 36 lb. magnet system that has to be externally supported, an external calibrated power supply, power consumption, and heat....right where you don't want it, in the voice coil gap. Modern magnet system design, using FEA and computer simulation, is a very highly advanced science, that has already addressed both flux density and flux stability, so I don't see how these field coils bring anything further to the table. The overall challenge for system sensitivity depends on the bass section anyway, far more than the upper frequencies, and that's a PM design in this system. So the field coil strikes me as a "gimmick" more than anything else, to complement the "vintage vibe" of the system as a whole.. Imagine the cost impact just based on the added weight, steel, copper, bracing, power supplies, etc. This is not going to be a "bargain basement" speaker.