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Low-latency multi-driver adaptive noise canceling (ANC) system for a personal audio device

  • US 9,955,250 B2
  • Filed: 07/06/2016
  • Issued: 04/24/2018
  • Est. Priority Date: 03/14/2013
  • Status: Active Grant
First Claim
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1. A personal audio system, comprising:

  • a source of audio for reproduction, wherein the source of audio provides a source audio signal;

    a first transducer for reproducing high-frequency content of the source audio signal for playback to a listener and a first anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the first transducer, wherein the first transducer is a high-frequency transducer of an earspeaker;

    a second transducer for reproducing low-frequency content of the source audio signal for playback to the listener and a second anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the second transducer, wherein the second transducer is a low-frequency transducer of the earspeaker;

    a third transducer for reproducing high-frequency content of a second source audio signal and a third anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the third transducer;

    a fourth transducer for reproducing low-frequency content of the second source audio signal and a fourth anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the fourth transducer;

    at least one microphone for providing at least one microphone signal indicative of the ambient audio sounds; and

    a processing circuit that generates the first anti-noise signal from the at least one microphone signal using a first adaptive filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal, wherein the processing circuit generates the second anti-noise signal from the at least one microphone signal using a second adaptive filter to reduce the presence of the ambient audio sounds at the first transducer and the second transducer in conformity with the at least one microphone signal, wherein the processing circuit restricts content of the first anti-noise signal to a first predetermined frequency range by limiting a first frequency response of the first adaptive filter to the first predetermined frequency range, and wherein the processing circuit restricts content of the second anti-noise signal to a second predetermined frequency range by limiting a second response of the second adaptive filter to a second predetermined frequency range, wherein the first predetermined frequency range and the second predetermined frequency range are substantially different, and wherein the processing circuit further generates the third anti-noise signal and the fourth anti-noise signal from the at least one microphone signal using a third filter to reduce the presence of the ambient audio sounds at the third transducer in conformity with the at least one microphone signal, wherein the processing circuit generates the fourth anti-noise signal from the at least one microphone signal using a fourth filter to reduce the presence of the ambient audio sounds at the fourth transducer in conformity with the at least one microphone signal.

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