Patent ID: 8712065

Claim:
A method for controlling and limiting voice coil displacement of an electro dynamic transducer, the method comprising: predicting an instantaneous displacement signal based on a digital audio input signal; delaying the predicted displacement signal a predefined number of samples; controlling the delayed, predicted displacement signal using the predicted displacement signal as input, by: applying a gain function which multiplies a calculated gain factor, g(n), with the delayed predicted displacement signal, the calculated gain factor being calculated based on a ratio between the predicted instantaneous displacement signal and a displacement threshold x d,th determined by a total system gain and transducer characteristics, given as ratio(n)=x d,th /x d (n); applying an inverse filter structure to transform the predicted displacement signal into a signal domain of the digital audio input signal; amplifying the controlled signal domain signal; and applying the amplified controlled signal domain signal to the electro dynamic transducer.