Method and device for detecting a displacement and movement of a sound producing unit of a woofer

摘要

The invention relates to a system for adjusting a response of a loudspeaker system. The loudspeaker system comprises a woofer (4) installed in a housing (22), said woofer (4) comprising a woofer cone (4.2). The system also comprises a transmitter (6.1) for transmitting an ultrasonic audio signal towards the woofer cone (4.2), a receiver (6.2) for receiving the ultrasonic audio signal; and a detection unit (9) for determining the position of the woofer cone (4.2) on the basis of a difference between the phase of the reflected ultrasonic audio signal with respect to the ultrasonic audio signal transmitted from the transmitter (6.1). The system also comprises a control unit (5) for adjusting the a spring constant of the membrane (4.2) of the loudspeaker system on the basis of the determined position. The invention also relates to a method for adjusting a response of a loudspeaker system, to a module to be used in the system, and a computer program product comprising computer code for adjusting a response of the loudspeaker system.