alt Hacker NewsThey have visible pickups, which presumably have a permanent magnet core.
But how are the resonators getting 'plucked'? Is it the same electromagnet as the pickup or a separate one? I can't imagine those two modes would work well. (i.e. dumping current across the coil would make the magnet want to escape)
Perhaps there's a field coil instead of a permanent magnet?
My guess is that it uses magnetic fields to resonate the bars (kinda like an ebow). Any plucking types sounds are probably done with filter/envelopes within the electronics.