Systems and methods for use of adaptive secondary path estimate to control equalization in an audio device
First Claim
1. A personal audio device, comprising:
- a personal audio device housing;
a transducer coupled to the housing for reproducing an output audio signal including an equalized source audio signal for playback to a listener;
an error microphone coupled to the housing in proximity to the transducer for providing an error microphone signal indicative of an acoustic output of the transducer;
a processing circuit that implements;
a secondary path estimate filter for modeling an electro-acoustical path of a source audio signal through the transducer;
a secondary path estimate filter coefficient control block that shapes a response of the secondary path estimate filter in conformity with the error microphone signal;
an adjustable equalization filter having a response that generates an equalized source audio signal from the source audio signal to account for effects of changes in the electro-acoustical path of the source audio signal; and
an equalizer coefficient control block that adapts the response of the adjustable equalization filter in response to changes in the response of the secondary path estimate filter to shape the response of the adjustable equalization filter in conformity with a response of a target filter by adapting the response of the adjustable equalization filter to minimize a difference between the response of the target filter and the response of the adjustable equalization filter;
wherein;
the target filter has a response equal to a ratio of a response of a fixed ideal filter to the response of the secondary path estimate filter; and
the response of the fixed ideal filter is a pre-calculated transfer function desired to be applied by the electro-acoustical path.
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Accused Products
Abstract
In accordance with embodiments of the present disclosure, an adjustable equalization filter may have a response that generates an equalized source audio signal from a source audio signal to account for effects of changes in an electro-acoustical path of the source audio signal to a transducer. An equalizer coefficient control block may adapt the response of the adjustable equalization filter in response to changes in a response of a secondary path estimate filter for modeling the electro-acoustical path of a source audio signal through the transducer, wherein a response of the secondary path estimate filter is adapted in conformity with an error microphone signal indicative of the acoustic output of the transducer.
283 Citations
30 Claims
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1. A personal audio device, comprising:
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a personal audio device housing; a transducer coupled to the housing for reproducing an output audio signal including an equalized source audio signal for playback to a listener; an error microphone coupled to the housing in proximity to the transducer for providing an error microphone signal indicative of an acoustic output of the transducer; a processing circuit that implements; a secondary path estimate filter for modeling an electro-acoustical path of a source audio signal through the transducer; a secondary path estimate filter coefficient control block that shapes a response of the secondary path estimate filter in conformity with the error microphone signal; an adjustable equalization filter having a response that generates an equalized source audio signal from the source audio signal to account for effects of changes in the electro-acoustical path of the source audio signal; and an equalizer coefficient control block that adapts the response of the adjustable equalization filter in response to changes in the response of the secondary path estimate filter to shape the response of the adjustable equalization filter in conformity with a response of a target filter by adapting the response of the adjustable equalization filter to minimize a difference between the response of the target filter and the response of the adjustable equalization filter;
wherein;the target filter has a response equal to a ratio of a response of a fixed ideal filter to the response of the secondary path estimate filter; and the response of the fixed ideal filter is a pre-calculated transfer function desired to be applied by the electro-acoustical path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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receiving an error microphone signal indicative of an acoustic output of a transducer; modeling an electro-acoustical path of a source audio signal with a secondary path estimate filter; adapting a response of the secondary path estimate filter in conformity with the error microphone signal; generating an equalized source audio signal from a source audio signal by filtering the source audio signal with an adjustable equalization filter to account for effects of changes in the electro-acoustical path of the source audio signal; and adapting a response of the adjustable equalization filter in response to changes in the response of the secondary path estimate filter to minimize a difference between the response of the target filter and the response of the adjustable equalization filter;
wherein;the target filter has a response equal to a ratio of a response of a fixed ideal filter to the response of the secondary path estimate filter; and the response of the fixed ideal filter is a pre-calculated transfer function desired to be applied by the electro-acoustical path. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An integrated circuit comprising:
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an output for providing a signal to a transducer including an equalized source audio signal for playback; an error microphone input for receiving an error microphone signal indicative of an acoustic output of the transducer; and a processing circuit that implements; a secondary path estimate filter for modeling an electro-acoustical path of a source audio signal through the transducer; a secondary path estimate filter coefficient control block that shapes a response of the secondary path estimate filter in conformity with the error microphone signal; an adjustable equalization filter having a response that generates the equalized source audio signal from the source audio signal to account for effects of changes in the electro-acoustical path of the source audio signal; and an equalizer coefficient control block that adapts the response of the adjustable equalization filter in response to changes in the response of the secondary path estimate filter to shape the response of the adjustable equalization filter in conformity with a response of a target filter by adapting the response of the adjustable equalization filter to minimize a difference between the response of the target filter and the response of the adjustable equalization filter;
wherein;the target filter has a response equal to a ratio of a response of a fixed ideal filter to the response of the secondary path estimate filter; and the response of the fixed ideal filter is a pre-calculated transfer function desired to be applied by the electro-acoustical path. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification