Field coil drivers ae wonderful and a headache at the same time. I have two friends that went down that path. When the stars aligned, they were some of the best drivers I’ve heard. But they can be a pain to get set up right and the power supplies for the driver’s field coil must be very good and need clean power or you will have issues i.e. hum etc. I’m sure a good part of that cost is those power supplies they can make or break a field coil driver. Both my friends had to spend upwards of $3000 for those power supplies and even then, they had their moments. But and a big but when you have them dialed in, they are wonderful. Not sure if his designs will have adjustability in the field coil levels as that can also make for interesting differences in sound.
One of my friends uses Supra vox field coils and the other Voxativ. Both in open baffles, the Vox set up is much more expensive all around and lovely.
