An apparatus related to a magnetic circuit design is disclosed. The apparatus includes a magnetic assembly and an electrically-conductive mobile member. The magnetic assembly includes an inner magnet, an outer magnet, an inner cap, an outer cap and a washer. The magnetic assembly is configured to produce a magnetic field having a zone of operation between the inner cap and the outer cap. The zone of operation has substantially uniform magnetic field strength. The zone of operation has magnetic field directions substantially perpendicular to an ideal motion direction. The electrically-conductive mobile member is disposed in the zone of operation of the magnetic field and electrically coupled to a diaphragm of a driver. The electrically-conductive mobile member is configured to move within the zone of operation of the magnetic field in response to the magnetic field when an alternating current is passed through the electrically-conductive mobile member.