Abstract: A noise-cancellation system includes a noise-cancellation filter in communication with at least one speaker, the noise-cancellation filter generating a noise-cancellation signal that, when actuated by the at least one speaker, cancels noise within at least one cancellation zone; and an amplifier disposed between the noise-cancellation filter and the speaker, the amplifier applying a first scaling gain to the noise-cancellation signal and outputting an scaled noise-cancellation signal, the scaled noise-cancellation signal being a linear reduction of the noise-cancellation signal when the first scaling gain is less than unity, wherein the first scaling gain is set to less than unity in response to a signal representative of the noise-cancellation signal exceeding a threshold.

Abstract: Methods, systems, and computer-readable media are provided for detecting voice activity. A primary signal is configured to include a speech component representative of a user's speech when the user is speaking in a detection region, or environment. A reference signal is configured to include a reduced speech component relative to the primary signal. One or more conditions of the detection region is/are detected, and a threshold value is selected (or, optionally, calculated) based upon the detected condition(s). The primary signal is compared to the reference signal, with respect to the selected threshold value. An indication of whether the user is speaking is selectively output, based at least in part upon the comparison.

Abstract: Audio systems and methods are provided that receive a sound management input signal as a reference signal to remove related content from a microphone signal in, e.g., an automotive hands-free system. The sound management signal may provide an acoustic augmentation to reduce, enhance, or create an acoustic effect, e.g., of an engine, motor, or other operating components. A signal processor receives the sound management signal and the microphone signal, and reduces or removes the sound management signal components from the microphone signal.

Abstract: Audio systems, methods, and computer readable media for managing audio headroom are provided. At least two input signals are received and combined. The combined signals is compared to a threshold value and may be adjusted if the combined signal exceeds the threshold value. A gain is applied to the first input signal based upon the combined signal being above the threshold value. The gain may be an attenuating gain. Accordingly, a gain is applied to at least one input signal to reduce the input signal when a combination of the input signals exceeds a threshold value.

Abstract: A method includes receiving a set of time domain samples representing audio captured using one or more microphones, and generating, from the time domain samples, a spectrum comprising a set of frequency domain coefficients, each coefficient representing a frequency bin corresponding to a range of frequencies. The method also includes adjusting the spectrum to generate a smoothed spectrum, wherein generating the smoothed spectrum includes determining that a magnitude of a first frequency domain coefficient is less than a threshold, and in response, replacing the first frequency domain coefficient by a value computed as a function of a plurality of frequency domain coefficients that include the first frequency domain coefficient. The method further includes generating an audio signal based on time domain samples computed using the smoothed spectrum.

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: A noise-cancellation system includes a noise-cancellation filter in communication with at least one speaker, the noise-cancellation filter generating a noise-cancellation signal that, when actuated by the at least one speaker, cancels noise within at least one cancellation zone; and an amplifier disposed between the noise-cancellation filter and the speaker, the amplifier applying a first scaling gain to the noise-cancellation signal and outputting an scaled noise-cancellation signal, the scaled noise-cancellation signal being a linear reduction of the noise-cancellation signal when the first scaling gain is less than unity, wherein the first scaling gain is set to less than unity in response to a signal representative of the noise-cancellation signal exceeding a threshold.

Abstract: A method includes receiving multiple samples of time-domain data that includes noise, computing a first two-dimensional (2D) time-frequency representation of the time domain data, and processing the first time-frequency representation using a time-frequency noise reduction mask to generate a second, noise-reduced time-frequency representation of the time domain data. The method also includes generating a time domain output based on the noise-reduced time-frequency representation.

Abstract: A method includes receiving multiple frames of time-domain data that includes noise, and computing, for a first frame of the multiple frames, a frequency domain value for each of multiple frequency bins, each frequency bin representing a corresponding range of frequencies. The method also includes determining that a first frequency domain value corresponding to a first frequency bin is less than or equal to a first threshold value, and in response, updating the first frequency domain value based on a function of (i) a smoothing parameter, and (ii) a second frequency domain value corresponding to the first frequency bin. The second frequency domain value is computed using one or more preceding frames of the multiple frames. The method further includes determining a noise floor corresponding to the first frequency bin using the updated first frequency domain value.

Abstract: A method includes receiving multiple samples of time-domain data that includes noise, computing a first two-dimensional (2D) time-frequency representation of the time domain data, and processing the first time-frequency representation using a time-frequency noise reduction mask to generate a second, noise-reduced time-frequency representation of the time domain data. The method also includes generating a time domain output based on the noise-reduced time-frequency representation.

Abstract: A method includes receiving a set of time domain samples representing audio captured using one or more microphones, and generating, from the time domain samples, a spectrum comprising a set of frequency domain coefficients, each coefficient representing a frequency bin corresponding to a range of frequencies. The method also includes adjusting the spectrum to generate a smoothed spectrum, wherein generating the smoothed spectrum includes determining that a magnitude of a first frequency domain coefficient is less than a threshold, and in response, replacing the first frequency domain coefficient by a value computed as a function of a plurality of frequency domain coefficients that include the first frequency domain coefficient. The method further includes generating an audio signal based on time domain samples computed using the smoothed spectrum.

Abstract: A method includes receiving multiple frames of time-domain data that includes noise, and computing, for a first frame of the multiple frames, a frequency domain value for each of multiple frequency bins, each frequency bin representing a corresponding range of frequencies. The method also includes determining that a first frequency domain value corresponding to a first frequency bin is less than or equal to a first threshold value, and in response, updating the first frequency domain value based on a function of (i) a smoothing parameter, and (ii) a second frequency domain value corresponding to the first frequency bin. The second frequency domain value is computed using one or more preceding frames of the multiple frames. The method further includes determining a noise floor corresponding to the first frequency bin using the updated first frequency domain value.

Abstract: Audio systems and methods for suppressing residual echo are provided. First and second audio program content signals are received, and a residual signal from an echo canceler is received. A first spectral mismatch is determined based at least upon a cross power spectral density of the first program content signal and the residual signal. The first spectral mismatch is associated with an operational state of the audio system. The residual signal is filtered to reduce residual echo, based at least upon the first spectral mismatch, a spectral density of the first program content signal, and a spectral density of the residual signal.

Abstract: Audio systems and methods are provided that receive a sound management input signal as a reference signal to remove related content from a microphone signal in, e.g., an automotive hands-free system. The sound management signal may provide an acoustic augmentation to reduce, enhance, or create an acoustic effect, e.g., of an engine, motor, or other operating components. A signal processor receives the sound management signal and the microphone signal, and reduces or removes the sound management signal components from the microphone signal.

Abstract: In a vehicle equipped with a vehicle sound system, determining a virtual fixed gear ratio; determining a virtual RPM based on the virtual fixed gear ratio; generating a set of harmonic signals based on the virtual RPM, the harmonic signals being sine-wave signals proportional to harmonics of the virtual RPM; processing the harmonic signals to produce a set of processed harmonic signals; and in the vehicle sound system, transducing the processed harmonic signals to acoustic energy thereby to produce an engine sound within a passenger cabin of the vehicle.

Abstract: Audio systems and methods for suppressing residual echo are provided. First and second audio program content signals are received, and a residual signal from an echo canceler is received. A first spectral mismatch is determined based at least upon a cross power spectral density of the first program content signal and the residual signal. The first spectral mismatch is associated with an operational state of the audio system. The residual signal is filtered to reduce residual echo, based at least upon the first spectral mismatch, a spectral density of the first program content signal, and a spectral density of the residual signal.

Abstract: Audio systems and methods are provided to reduce echo content in an audio signal. The systems and methods receive an audio signal and sound stage rendering parameter(s), and select a set of filter coefficients to filter the audio signal to provide an estimated echo signal. The estimated echo signal is subtracted from a microphone signal to provide an output signal with reduced echo content. The set of filter coefficients are selected based upon the sound stage rendering parameter(s) from among a plurality of stored sets of filter coefficients.

Abstract: The technology described in this document can be embodied in a method for processing an input signal that represents a signal of interest captured in the presence of noise to generate a de-noised estimate of the signal of interest. The method includes receiving an input signal representing a signal of interest captured in the presence of noise. The method also includes processing at least a portion of the input signal using a digital filter to generate a filtered signal, the digital filter configured to suppress at least a portion of spectrum of the noise. The method further includes processing the filtered signal using a first neural network to generate a de-noised estimate of the signal of interest, wherein the first neural network is trained to compensate for distortions introduced by the digital filter in the signal of interest.

Abstract: Systems and methods providing engine harmonic enhancement receive a first signal representative of a load on an engine and generate a control parameter based on the first signal. One or more harmonic scaling elements generate a scaled version of an engine harmonic signal based on the control parameter. Each harmonic scaling element includes a harmonic specific mapping element for mapping the control parameter to a scaling factor, wherein at least some of the scaling factor values of the harmonic specific mapping element are mapped to control parameter values associated with a negative load on the engine.

Abstract: Audio systems and methods are provided to reduce echo content in an audio signal. The systems and methods receive an audio signal and sound stage rendering parameter(s), and select a set of filter coefficients to filter the audio signal to provide an estimated echo signal. The estimated echo signal is subtracted from a microphone signal to provide an output signal with reduced echo content. The set of filter coefficients are selected based upon the sound stage rendering parameter(s) from among a plurality of stored sets of filter coefficients.