Abstract: Systems, methods, and machine-readable storage devices that receive an input signal representing audio captured using a microphone. The input signal includes portions that represent acoustic output from one or more audio sources, and a portion that represents other acoustic energy in the environment. A frequency domain representation of the input signal is iteratively modified to substantially reduce effects due to all but a selected one of the portions, from which an estimate of the power spectral density, PSD, of the selected portion is determined. Based upon the estimated PSD a noise or echo component is reduced, or a replacement noise is provided. The iterative modification involves a diagonalization of the cross-spectral density matrix to remove content coherent with a first audio input from the auto and cross-spectra of other signals.

Abstract: Systems and methods for controlling an environment of a vehicle receive information about a characteristic of at least one of the vehicle's operation, the vehicle's location, and an operator of the vehicle. The information is analyzed to assess a driving condition. An environmental setting of the vehicle is adjusted based upon the assessed driving condition.

Abstract: An acoustic echo canceller includes an adaptive filter and a double-talk detector. The adaptive filter includes a linear filter and a coefficient calculator. The linear filter has a transfer function that is controlled by a set of variable filter coefficients and that is configured to cancel an estimate of echo in a microphone signal to provide an output signal. The coefficient calculator is configured to update the set of variable filter coefficients based on a variable adaptation rate. The double-talk detector is configured to calculate changes in the energy of the variable filter coefficients (between updates of the coefficients). The acoustic echo canceller is configured to adjust the variable adaptation rate based on whether the energy of the variable filter coefficients is determined to be either oscillating or steadily changing (increasing or decreasing).

Abstract: An active noise reduction system using adaptive filters. A method of operation the active noise reduction system includes smoothing a stream of leakage factors. The frequency of a noise reduction signal may be related to the engine speed of an engine associated with the system within which the active noise reduction system is operated. The engine speed signal may be a high latency signal and may be obtained by the active noise reduction system over audio entertainment circuitry.

Abstract: An acoustic echo canceller includes an adaptive filter and a double-talk detector. The adaptive filter includes a linear filter and a coefficient calculator. The linear filter has a transfer function that is controlled by a set of variable filter coefficients and that is configured to cancel an estimate of echo in a microphone signal to provide an output signal. The coefficient calculator is configured to update the set of variable filter coefficients based on a variable adaptation rate. The double-talk detector is configured to calculate changes in the energy of the variable filter coefficients (between updates of the coefficients). The acoustic echo canceller is configured to adjust the variable adaptation rate based on whether the energy of the variable filter coefficients is determined to be either oscillating or steadily changing (increasing or decreasing).

Abstract: A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine speed, and where the active noise reduction system comprises one or more adaptive filters that use a filter coefficient to modify the amplitude and/or phase of a noise cancellation reference signal and output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, where the value of the coefficient is related to an adaptive filter leakage factor. Changes in the engine speed, based on the input signal that is related to the vehicle engine operation, are monitored. In response to changes in the engine speed, the adaptive filter leakage factor is temporarily modified.

Abstract: An active noise reduction system using adaptive filters. A method of operation the active noise reduction system includes smoothing a stream of leakage factors. The frequency of a noise reduction signal may be related to the engine speed of an engine associated with the system within which the active noise reduction system is operated. The engine speed signal may be a high latency signal and may be obtained by the active noise reduction system over audio entertainment circuitry.

Abstract: A method of virtually tuning an audio system that incorporates an acoustic compensation system, where the audio system is adapted to play audio signals in a listening environment over one or more sound transducers. The acoustic compensation system has an audio sensor located at a sensor location in the listening environment. The transfer functions from each sound transducer to the audio sensor location are inherent. The method contemplates recording noise at the sensor location, and creating virtual transfer functions from each sound transducer to the sensor location based on the inherent transfer functions from each sound transducer to the sensor location. Audio signals are processed through the virtual sound transducer to sensor location transfer functions. A virtual sensor signal is created by combining the audio signals processed through the virtual sound transducer to sensor location transfer functions with the noise recorded at the sensor location.

Abstract: A headliner assembly for a vehicle includes a headliner and a microphone. The headliner is configured for attachment to the vehicle such that the headliner separates a passenger cabin of the vehicle from a roof panel of the vehicle and such that a first surface of the headliner faces the roof panel, and an opposite, second surface of the headliner faces the passenger cabin. The microphone is mounted along the second surface of the headliner such that, when installed in the vehicle, the headliner is disposed between the microphone and the roof panel.

Abstract: A system, device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an adaptive feed-forward noise reduction system input sine wave at a frequency to be cancelled, and where the adaptive feed-forward noise reduction system includes an adaptive filter that outputs noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, and further includes an input transducer with an output signal that is a source of a control signal for the adaptive filter. The output signal of the input transducer is filtered before it reaches the adaptive filter so as to reduce the level of the output signal of the input transducer at one or more frequencies that are close to the frequency of the input sine wave.

Abstract: A vehicle audio system that includes a source of audio signals, which may include both entertainment audio signals and announcement audio signals, speakers for radiating audio signals, and spatial enhancement circuitry comprising circuitry to avoid applying spatial enhancement processing to the announcement audio signals.

Abstract: A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine operation, and where the active noise reduction system comprises one or more adaptive filters that output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise. The engine harmonic noise level is estimated from the input signal that is related to the vehicle engine operation, and the output of the transducers is limited based on the estimate of the engine harmonic noise level.

Abstract: A headliner assembly for a vehicle includes a headliner and a microphone. The headliner is configured for attachment to the vehicle such that the headliner separates a passenger cabin of the vehicle from a roof panel of the vehicle and such that a first surface of the headliner faces the roof panel, and an opposite, second surface of the headliner faces the passenger cabin. The microphone is mounted along the second surface of the headliner such that, when installed in the vehicle, the headliner is disposed between the microphone and the roof panel.

Abstract: A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine speed, and where the active noise reduction system comprises one or more adaptive filters that use a filter coefficient to modify the amplitude and/or phase of a noise cancellation reference signal and output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, where the value of the coefficient is related to an adaptive filter leakage factor. Changes in the engine speed, based on the input signal that is related to the vehicle engine operation, are monitored. In response to changes in the engine speed, the adaptive filter leakage factor is temporarily modified.

Abstract: A system, device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an adaptive feed-forward noise reduction system input sine wave at a frequency to be cancelled, and where the adaptive feed-forward noise reduction system includes an adaptive filter that outputs noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, and further includes an input transducer with an output signal that is a source of a control signal for the adaptive filter. The output signal of the input transducer is filtered before it reaches the adaptive filter so as to reduce the level of the output signal of the input transducer at one or more frequencies that are close to the frequency of the input sine wave.

Abstract: A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine operation, and where the active noise reduction system comprises one or more adaptive filters that output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise. The engine harmonic noise level is estimated from the input signal that is related to the vehicle engine operation, and the output of the transducers is limited based on the estimate of the engine harmonic noise level.

Abstract: A method for determining leakage factors or adaptation rates, or both, for adaptive filters in an active noise reduction system. The leakage factor or adaptation rate, or both, may vary depending on a parameter of an input reference signal. The parameter may include one or more of reference signal input frequency, rate of change of reference input signal frequency, if a predetermined triggering condition exits, or if a predetermined event has occurred.

Abstract: A method of virtually tuning an audio system that incorporates an acoustic compensation system, where the audio system is adapted to play audio signals in a listening environment over one or more sound transducers. The acoustic compensation system has an audio sensor located at a sensor location in the listening environment. The transfer functions from each sound transducer to the audio sensor location are inherent. The method contemplates recording noise at the sensor location, and creating virtual transfer functions from each sound transducer to the sensor location based on the inherent transfer functions from each sound transducer to the sensor location. Audio signals are processed through the virtual sound transducer to sensor location transfer functions. A virtual sensor signal is created by combining the audio signals processed through the virtual sound transducer to sensor location transfer functions with the noise recorded at the sensor location.

Abstract: A vehicle external warning sound generation system and method. A transducer generates warning sounds external to the vehicle in response to an input sound signal. A sensor senses sound external to the vehicle and has an output signal that represents both sensed ambient noise and sensed warning sounds. A processing system, responsive to the sensor output signal, generates the sound signal that is provided to the transducer. The processing system includes an adaptive filter which reduces the level of the warning sounds in the sensor output signal, so that mostly ambient noise remains.

Abstract: A method for determining leakage factors or adaptation rates, or both, for adaptive filters in an active noise reduction system. The leakage factor or adaptation rate, or both, may vary depending on a parameter of an input reference signal. The parameter may include one or more of reference signal input frequency, rate of change of reference input signal frequency, if a predetermined triggering condition exits, or if a predetermined event has occurred.