Ironless Loudspeakers

The paper notes the drawbacks of classical loudspeaker motors: the inductance varies with the coil's position, there is a reluctant effect, and eddy currents appear because of the iron in the motor. It then presents ironless structures of loudspeaker motors to eliminate these drawbacks. These structures are studied with the use of Coulomb's model of permanent magnets, which affords analytical calculations. Thus, a design can be optimized to create a uniform, high-level induction in the space where the coil moves.