A thermoacoustic device for sound reproduction

Abstract

Many current research efforts focus on alternative electroacoustic transduction devices having no moving parts, in order to achieve sufficient audio performance from compact solid state devices. Thermoacousticloudspeakers are transducers based on the conversion of A/C current signals to thermal energy, causing a local fluctuation of air pressure which generates acoustic waves. A thermoacoustic actuator does not involve any movement of solid components in order to generate an acoustic wave and it is based on a mechanism of a "virtual" piston produced by vibrating air molecules via alternating heat transfer to the medium. This work examines such novel and alternative audio transduction technologies based on a novel hybrid thermoacoustictransducer prototype which was developed at the University of Patras through the cooperation between Audio and Acoustic Technology Group and Solid State Physics Laboratory. This hybrid solid state device without moving parts is based on the thermoacoustic method of sound reproduction and preliminary measurements of its performance are presented. The theoretical principles of these systems are also simulated, resulting into comparisons with the measured performance of the prototype.