Speaker distortion compensation device and speaker unit

A speaker distortion compensation device configured to compensate for distortion in an output from a speaker with respect to an input signal, the speaker distortion compensation device comprising:

• a sensor configured to detect vibration of a vibration system included in the speaker;
• a non-linearity compensation filter configured to accept the input signal;
• a tunable filter configured to accept an output from the non-linearity compensation filter and to output an output signal that drives the speaker;
• an adaptive algorithm execution unit configured to execute a predetermined adaptive algorithm to perform an adaptive operation in which a transfer function of the tunable filter is updated so that vibration detected by the sensor does not undergo distortion with respect to the input signal;
• and
• a controller configured to perform, as an initial setting operation for the speaker distortion compensation device, an operation in which the controller calculates a non-linear parameter of the speaker as an active non-linear parameter and sets, in the non-linearity compensation filter, a transfer function that compensates for distortion in the output from the speaker with respect to the input signal, the distortion being due to the calculated active non-linear parameter;
• wherein in the initial setting operation, the controller is configured to:
• drive the speaker by using a predetermined test signal and measure a response from the speaker as a measured response value, the response being measured from vibration of the vibration system, the vibration being detected by the sensor with respect to the test signal,
• calculate error between the measured response value and a theoretical response value, which is a theoretical value of the response from the speaker when the non-linear parameter of the speaker, the non-linear parameter being theoretically determined from design specifications of the speaker, is taken as a non-linear parameter theoretical value and the non-linear parameter theoretical value is the non-linear parameter of the speaker, and
• calculate, when the calculated error is smaller than a threshold level, the non-linear parameter theoretical value as the active non-linear parameter.