Patent ID: 7289637

Claim:
A method for automatically adjusting at least one filter parameter of at least one digital equalizer that is a component of a reproduction device for an audio signal in a vehicle passenger compartment, comprising: ascertaining an acoustical frequency response of the vehicle passenger compartment; determining an inadequacy in an acoustics of the vehicle passenger compartment in the form of one of a local maxima and a local minima in the acoustical frequency response; automatically adjusting the at least one filter parameter so that at least a portion of the inadequacy is compensated for; and storing a plurality of normalized curve patterns of different quality for the automatic adjustment of the at least one filter parameter, wherein: each determined local maximum in the acoustical frequency response is a potential center frequency of the at least one digital equalizer; for each determined local maximum in the acoustical frequency response: for each of the normalized curve patterns: (a) the center frequency of the respective curve pattern is shifted to the respective local maximum, (b) an attenuation is determined by scaling the respective curve pattern to the level of the respective local maximum, (c) the filter corresponding to the respective scaled curve pattern is used on the acoustical frequency response to output a filtered frequency response, and (d) a deviation of the filtered frequency response from a target frequency response is determined, the deviation representing a corresponding error value; and the performance of (a)-(d) for each of the plurality of curve patterns results in as many error values for the respective potential center frequency as there are curve patterns stored; and those of the at least one filter parameter of a particular one of the shifted and scaled curve patterns that has led to a smallest one of the error values are taken as the basis for the automatic adjustment of the at least one digital equalizer.