Systems and methods for providing adaptive playback 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 and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer;
an error microphone coupled to the housing in proximity to the transducer for providing an error microphone signal indicative of the acoustic output of the transducer and the ambient audio sounds at the transducer;
one or more processing circuits that implement;
a noise cancellation system that generates the anti-noise signal to reduce the presence of the ambient audio sounds heard by the listener based at least on the error microphone signal;
an adaptive playback equalization system that generates the equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of the adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal, wherein the adaptive playback equalization system comprises;
an adaptive equalization filter having a response that generates the equalized source audio signal from the source audio signal to reduce the effects of an electro-acoustical path of the source audio signal through the transducer;
a coefficient control block that shapes the response of the adaptive equalization filter in conformity with the error microphone signal and the source audio signal by adapting the response of the adaptive equalization filter to minimize the difference between the error microphone signal and the source audio signal; and
a secondary path estimate filter for modeling the electro-acoustical path and having a response that generates a secondary path estimate from the source audio signal and wherein the coefficient control block shapes the response of the adaptive equalization filter in conformity with the secondary path estimate and a delay corrected error, wherein the delay corrected error is based on a difference between the error microphone signal and a delayed source audio signal;
a noise injection portion for injecting respective noise signals into the secondary path estimate and the delay corrected error in order to bias, to below a predetermined maximum, a magnitude of the response of the adaptive equalization filter corresponding to a frequency in which the response of the secondary path estimate filter is substantially zero.
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Accused Products
Abstract
In accordance with systems and methods of the present disclosure, a method may include receiving an error microphone signal indicative of an acoustic output of a transducer and ambient audio sounds at the acoustic output of the transducer. The method may also include generating an anti-noise signal to reduce the presence of the ambient audio sounds at the acoustic output of the transducer based at least on the error microphone signal. The method may further include generating an equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of the adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal. The method may additionally include combining the anti-noise signal with the equalized source audio signal to generate an audio signal provided to the transducer.
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Citations
33 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 and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer; an error microphone coupled to the housing in proximity to the transducer for providing an error microphone signal indicative of the acoustic output of the transducer and the ambient audio sounds at the transducer; one or more processing circuits that implement; a noise cancellation system that generates the anti-noise signal to reduce the presence of the ambient audio sounds heard by the listener based at least on the error microphone signal; an adaptive playback equalization system that generates the equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of the adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal, wherein the adaptive playback equalization system comprises; an adaptive equalization filter having a response that generates the equalized source audio signal from the source audio signal to reduce the effects of an electro-acoustical path of the source audio signal through the transducer; a coefficient control block that shapes the response of the adaptive equalization filter in conformity with the error microphone signal and the source audio signal by adapting the response of the adaptive equalization filter to minimize the difference between the error microphone signal and the source audio signal; and a secondary path estimate filter for modeling the electro-acoustical path and having a response that generates a secondary path estimate from the source audio signal and wherein the coefficient control block shapes the response of the adaptive equalization filter in conformity with the secondary path estimate and a delay corrected error, wherein the delay corrected error is based on a difference between the error microphone signal and a delayed source audio signal; a noise injection portion for injecting respective noise signals into the secondary path estimate and the delay corrected error in order to bias, to below a predetermined maximum, a magnitude of the response of the adaptive equalization filter corresponding to a frequency in which the response of the secondary path estimate filter is substantially zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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receiving an error microphone signal indicative of an acoustic output of a transducer and ambient audio sounds at the acoustic output of the transducer; generating an anti-noise signal to reduce the presence of the ambient audio sounds at the acoustic output of the transducer based at least on the error microphone signal; generating an equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of an adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal, wherein the equalized source audio signal is generated by an adaptive equalization filter having a response that generates the equalized source audio signal from the source audio signal to reduce the effects of an electro-acoustical path of the source audio signal through the transducer, and the method further comprising shaping the response of the adaptive equalization filter in conformity with the error microphone signal and the source audio signal by adapting the response of the adaptive equalization filter to minimize the difference between the error microphone signal and the source audio signal; generating a secondary path estimate from the source audio signal by filtering the source audio signal with a secondary path estimate filter modeling an electro-acoustical path of the source audio signal; and
wherein shaping the response of the adaptive equalization filter comprises shaping the response of the adaptive equalization filter in conformity with the secondary path estimate and a delay corrected error, wherein the delay corrected error is based on a difference between the error microphone signal and a delayed source audio signal;injecting respective noise signals into the secondary path estimate and the delay corrected error in order to bias, to below a predetermined maximum, a magnitude of the response of the adaptive equalization filter corresponding to a frequency in which the response of the secondary path estimate filter is substantially zero; and combining the anti-noise signal with the equalized source audio signal to generate an audio signal provided to the transducer. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An integrated circuit for implementing at least a portion of a personal audio device, comprising:
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an output for providing a signal to a transducer including both an equalized source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer; an error microphone input for receiving an error microphone signal indicative of the acoustic output of the transducer and the ambient audio sounds at the transducer; and one or more processing circuits that implement; a noise cancellation system that generates the anti-noise signal to reduce the presence of the ambient audio sounds heard by the listener based at least on the error microphone signal; and an adaptive playback equalization system that generates the equalized source audio signal from a source audio signal by adapting, based at least on the error microphone signal, a response of the adaptive playback equalization system to minimize a difference between the source audio signal and the error microphone signal;
wherein the adaptive playback equalization system comprises;an adaptive equalization filter having a response that generates the equalized source audio signal from the source audio signal to reduce the effects of an electro-acoustical path of the source audio signal through the transducer; a coefficient control block that shapes the response of the adaptive equalization filter in conformity with the error microphone signal and the source audio signal by adapting the response of the adaptive equalization filter to minimize the difference between the error microphone signal and the source audio signal; and a secondary path estimate filter for modeling the electro-acoustical path and having a response that generates a secondary path estimate from the source audio signal and wherein the coefficient control block shapes the response of the adaptive equalization filter in conformity with the secondary path estimate and a delay corrected error, wherein the delay corrected error is based on a difference between the error microphone signal and a delayed source audio signal; and a noise injection portion for injecting respective noise signals into the secondary path estimate and the delay corrected error in order to bias, to below a predetermined maximum, a magnitude of the response of the adaptive equalization filter corresponding to a frequency in which the response of the secondary path estimate filter is substantially zero. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification