piezoelectric loudspeaker[pē¦ā·zō·ə′lek·trik ′lau̇d‚spēk·ər]
a loudspeaker that utilizes a piezoelectric component for the conversion of electric oscillations in the audio-frequency range to mechanical vibrations. The piezoelectric loudspeakers that are most widely used have a square, flat piezoelectric component made of Rochelle salt. The apex of the cone-shaped diaphragm used as the sound emitter is affixed to the free corner of the piezoelectric component. Loudspeakers with piezoelectric elements produce poor quality sound, and their elements are not reliable. Nevertheless, because of their low cost and simple manufacture, they were produced in the USSR during the Great Patriotic War (1941–45) and the early postwar years.