Abstract
A new magnetic circuit for a low distortion loudspeaker has been studied using a finite element analysis considering a minor hysteresis loop. The magnetic materials in the vicinity of the voice coil are magnetized by fields both AC currents and a permanent magnet. A minor hysteresis loop is induced by this magnetization. The incremental permeability of minor hysteresis loop effects on the sound distortion. We calculated the flux distribution of the magnetic circuit using a finite element method, considering the incremental permeability of the minor hysteresis loop obtained by an experimental method. It is clarified the relation between the sound distortion caused by the flux distribution and the magnetic structure. The developed magnetic circuit has a pole piece which has a hole at the upper surface and which is located higher than the plate.
