Loudspeaker having a voice coil and a piezoelectric feedback transducer

摘要

Loudspeaker, in particular low-note loudspeaker, provided with a cone-shaped diaphragm having a coil form on which in addition to the voice coil is mounted a piezoelectric transducer in the form of a thin plate capable of pivotal movement. The output voltage of the transducer is degeneratively fed back to the input of an associated amplifier. The plate preferably is rectangular and suspended in rubber mounts along two opposed edges. The mounts form part of a mounting board provided with printed wiring on which an electronic transformation circuit is arranged. A shallow cup in which the mounting board is accommodated ensures that the piezoelectric plate is separated in an airtight manner from the coil form.