Sound reduction device for noise source in aircraft cabin has electroacoustic transducer comprising suspended membrane having spring stiffness and adjustment unit arranged to change spring stiffness

摘要

An electroacoustic transducer having mechanical values generates secondary sound wave as counter sound of primary sound wave generated by a noise source in narrow frequency ranges. The electroacoustic transducer comprises a suspended membrane having a spring stiffness and an adjustment unit arranged to change spring stiffness. - An error microphone set up to measure error signal of primary and secondary sound waves is coupled to a control unit to transmit error signal to the control unit. The control unit receives a reference signal of the noise source, and generates a control signal for changing the mechanical values of the electroacoustic transducer based on the reference signal and the error signal. - An INDEPENDENT CLAIM is also included for a sound reducing method for noise source in e.g. aircraft cabin.