Design of a flat-panel loudspeaker with giant magnetostrictive exciters

Abstract

A novel design has been undertaken to introduce solid resonant motion actuation in flat panel loudspeakers. The actuation of the vibration is obtained using direct magnetostrictive actuators or amplified magnetostrictive actuators with flexure hinges. Instead of one or two exciters, the proposed panel speakers have several micro-transducers vibrating coherently to produce sound and to form a Distributed Mode Loudspeaker (DML) sound system. The whole body vibration of the panel will eliminate the poor bass and impulse response associated with the present flat panel speakers. A matrix of miniature magnetostrictive actuators having magnet-coil assembly along with simulation using commercial simulation packages such as ANSYS and LSPCAD software explores the possibilities of using micro-actuators array for loudspeaker application. The paper discusses in details of the giant magenetostrictive exciter design, placement of the exciters, and choice of the panel materials as well as the test of several flat-panel loudspeaker prototypes.