PLANE LOUD SPEAKER

摘要

PURPOSE:To obtain a plane loud speaker which has excellent sound pressure characteristics and less strain over a wide range by detecting the bending strain of a plane diaphragm in the form of an electric signal and applying this electric signal to a driving coil. CONSTITUTION:A mechanoelectric transudcing element (e.g. piezoelectric element or strain gauge) is joined to the center part of the plane diaphragm 1. Through the mechanoelectric transducing element 10, the bending strain of the diaphragm is detected. The electric output of the element 10 is inverted in phase by an inverting amplifier circuit and inputted to a control coil 11. The control coil 11 is driven by the input of the electric signal to cancel the bending strain of the diaphragm.