ProggRob wrote on 05/04/16 at 04:37:15:I think I understand the merit of the field cool design, at least in theory. The magnetic field generated by the field coil isn't affected by the forces of the voice coil and so it exerts better control of the driver with less overshoot and therefore less distortion. The extra required power supply seems critical here, which could be $300 for an off the shelf unit or thousands for specialty designed tube-based units with very low ripple. Speakers like the Shindo Latour are of this design and have deity status in my mind (at least until I hear them) but perhaps I've exalted this technology unnecessarily. When I read comments like this it makes me wonder if the benefits of field coil are overblown?
"It's not practical. It can't be easily employed and is subject to more problems simply due to the increased parts count and design complexity. You are not going to find high frequency drivers that use an active magnetic structure short of electrostatic designs. There is some potential benefit in the additional power available though. Focal has decided to use the technology in the subwoofer of their Utopia EM systems. It allows more power to be delivered to the coil by any given amplifier than the ferro magnet. It is also adjustable, so that helps to tune the LF response to the room. And oh yeah, it's expensive. No reason in my pinion to go out of the way of 99% of the worlds best designs just to find a "full range" field coil speaker. It is an awkward answer searching for a niche problem to solve."
Good post Rob! They seem very drool worthy, however I've never heard any field coils and wonder if I've overdrawn conclusions of them and placed them on a pedestal just due to their exoticness. I also wonder how much of a difference they would make over something like the Voxativ Treo15 model (though Voxativ does have field coils as well, but they are priced only for people who have their own private islands).
ProggRob wrote on 05/04/16 at 04:41:18:Beowulf, pricing was $8500 without the power supply. You could buy a recommended $350 off-the-shelf power supply or the WVL supply for $2600 additional.
Although the PAP field coils do seem reasonably priced for what you get, that price alone puts them firmly out of my reach.
At any rate, I'm going to try and make it to T.H.E. Show in Newport this June ... hopefully the field coils will be demoing there and if so I'll report back (if I make it to the show that is).