Subwoofer loudspeaker

摘要

A subwoofer loudspeaker with a diaphragm driven by a rotating electric motor is characterised by the fact that the diaphragm is driven via a crank and a crank rod by a motor which is acted upon reversibly via a controllable power supply, an incremental encoder being arranged on the motor shaft, the angle-of-rotation-dependent signals of which encoder are compared with the control signal in a difference circuit (10) and the difference signal of the control circuit controlling the power supply. <IMAGE>