Method for automatically adjusting the filter parameters of a digital equalizer and reproduction device for audio signals for implementing such a method
First Claim
1. 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.
1 Assignment
0 Petitions
Accused Products
Abstract
A method is proposed for automatically adjusting the filter parameters—center frequency, quality and amplification or attenuation—of at least one digital equalizer which is a component of a reproduction device for audio signals in a vehicle passenger compartment. To that end, first of all, the acoustical frequency response of the passenger compartment is ascertained. The inadequacies in the acoustics of the passenger compartment in the form of local maxima and minima in the measured frequency response are then determined. On this basis, the filter parameters are adjusted automatically so that at least a portion of these inadequacies is compensated. A reproduction device for audio signals for implementing this method is also proposed.
137 Citations
14 Claims
-
1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A reproduction device for an audio signal, comprising:
-
a loudspeaker device; an audio processor that includes at least one digital equalizer; a control bus; at least one microphone including an evaluation device for detecting a signal emitted by the loudspeaker device into a vehicle passenger compartment and for determining a frequency response; a control processor connected to the audio processor via the a control bus, the control processor including an arrangement for determining an inadequacy in an acoustics of the vehicle passenger compartment and for automatically adjusting at least one filter parameter to compensate at least a portion of the inadequacy, the adjustment taking into account the frequency response; wherein; each determined local maximum of the frequency response is a potential center frequency of the at least one digital equalizer; for each determined local maximum of the frequency response; the arrangement is configured to, for each of a plurality of stored normalized curve patterns of different quality for the adjustment of the at least one filter parameter; (a) shift the center frequency of the respective curve pattern to the respective local maximum; (b) determine an attenuation by scaling the respective curve pattern to the level of the respective local maximum; (c) use the filter corresponding to the respective scaled curve pattern on the frequency response to output a filtered frequency response; and (d) determine a deviation of the filtered frequency response from a target frequency response, the deviation representing a corresponding error value; and the performance for the respective frequency response 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 the arrangement is configured to take those of the at least one filter parameter of one of the shifted and scaled curve patterns that has led to a smallest one of the error values as the basis for the automatic adjustment of the at least one digital equalizer. - View Dependent Claims (11, 12, 13, 14)
-
Specification