Patent ID: 7302077
Filing Date: 2007-11-27
Classification: H04R

Abstract:
1. An electromagnetic driver for a planar diaphragm loudspeaker having a plate, comprising: a soft magnetic core in an E-shaped form having three legs and a back, each leg having a free end; an alternating field exciter that is magnetically coupled to the soft magnetic core for generating a magnetic alternating flux that depends on a sound signal, in the soft magnetic core; a constant field exciter which is magnetically coupled to the soft magnetic core, for generating a constant magnetic flux in the soft magnetic core; and a soft magnetic element, which magnetically terminates the legs with at least one small induction gap and is located opposite the back, for coupling with the plate of the planar diaphragm loudspeaker, where the alternating flux and the constant flux superpose constructively at an outer leg of the magnetic core and destructively at another outer leg of the magnetic core, so that a resulting force or a resulting torque in the soft magnetic element is essentially linear with respect to the sound signal.