A method of suppressing residual echo includes calculating a spectral mismatch of an acoustic echo canceler based upon a program content signal and a residual signal; determining a set of filter coefficients based at least in part upon a selected spectral mismatch; filtering the residual signal based upon the set of filter coefficients; freezing the calculation of the selected spectral mismatch in response to detecting a double talk condition in the residual signal; waiting a predetermined hold period in response to detecting that the double talk condition has ended; and, after the predetermined hold period, resuming the calculation of the spectral mismatch based upon the program content signal and the residual signal.

A playback device is configured to receive, via a network interface, a source stream of audio including first and second channel streams of audio, and to produce, via respective first and second speaker drivers, a first channel audio output and a second channel audio output. The playback device is also configured to receive, via one or more microphones, a captured stream of audio including first and second portions corresponding to the respective first and second channel audio outputs. The playback device is also configured to combine at least the first channel stream of audio and the second channel stream of audio into a compound audio signal and perform acoustic echo cancellation on the compound audio signal and thereby produce an acoustic echo cancellation output, then to apply the acoustic echo cancellation output to the captured stream of audio and thereby increase a signal-to noise ratio of the captured stream of audio.

A playback device is configured to receive, via a network interface, a source stream of audio including first and second channel streams of audio, and to produce, via respective first and second speaker drivers, a first channel audio output and a second channel audio output. The playback device is also configured to receive, via one or more microphones, a captured stream of audio including first and second portions corresponding to the respective first and second channel audio outputs. The playback device is also configured to combine at least the first channel stream of audio and the second channel stream of audio into a compound audio signal and perform acoustic echo cancellation on the compound audio signal and thereby produce an acoustic echo cancellation output, then to apply the acoustic echo cancellation output to the captured stream of audio and thereby increase a signal-to noise ratio of the captured stream of audio.

A conversation support device includes: a speaker; a microphone; a noise source acquisition unit that acquires a noise signal indicating noise; a first calculator that calculates a transfer characteristic of a secondary path between the speaker and the microphone; an echo cancellation unit that cancels an echo by using the transfer characteristic of the secondary path; a second calculator that calculates a coefficient of an adaptive filter, based on the transfer characteristic of the secondary path and the noise signal; and an active noise cancellation controller that generates a noise cancelling signal by using the coefficient of the adaptive filter and the noise signal. The noise cancelling signal is for controlling cancellation of the noise.

A method of suppressing residual echo includes calculating a spectral mismatch of an acoustic echo canceler based upon a program content signal and a residual signal; determining a set of filter coefficients based at least in part upon a selected spectral mismatch; filtering the residual signal based upon the set of filter coefficients; freezing the calculation of the selected spectral mismatch in response to detecting a double talk condition in the residual signal; waiting a predetermined hold period in response to detecting that the double talk condition has ended; and, after the predetermined hold period, resuming the calculation of the spectral mismatch based upon the program content signal and the residual signal.

A steerable speaker array is provided, comprising a plurality of drivers arranged in a concentric, nested configuration formed by arranging the drivers in a plurality of concentric groups and placing the groups at different radial distances from a central point of the configuration. Each group is formed by a subset of the plurality of drivers being positioned at predetermined intervals from each other along a perimeter of the group. Also, the concentric groups are harmonically nested and rotationally offset from each other. An audio system is also provided comprising at least one steerable speaker array and a beamforming system configured to receive one or more input audio signals from an audio source, generate a separate audio output signal for each driver of the speaker array based on at least one of the input signals, and provide the audio output signals to the corresponding drivers to produce a beamformed audio output.

A voice communication technique by which superior echo canceling can be realized even in use of non-directional microphones is provided. When voice uttered by a near end speaker is defined as speaker's voice; sound obtained by emitting a received speech signal, which is a voice signal of a far end speaker, by a loudspeaker is defined as reproduction sound; a signal obtained by picking up an acoustic signal, which contains the speaker's voice and the reproduction sound, by a first microphone is defined as a first sound pickup signal; and a signal obtained by picking up an acoustic signal, which contains the speaker's voice and the reproduction sound, by a second microphone is defined as a second sound pickup signal, a voice communication device includes: a first subtraction unit that generates a first-subtracted first sound pickup signal that is a difference between a corrected sound pickup signal and the second sound pickup signal or the first sound pickup signal, the corrected sound pickup signal being obtained by correcting either one of the first sound pickup signal and the second sound pickup signal on the basis of an amplitude difference based on a difference between a distance d1 from the loudspeaker to the first microphone and a distance d2 from the loudspeaker to the second microphone (d2d1); and a second subtraction unit that generates a transmitted speech signal, which is to be transmitted to the far end speaker, by subtracting an adaptive-filtered second sound pickup signal, which is obtained by canceling echo, from the first-subtracted first sound pickup signal.

In at least one embodiment, an embedded Linux system is provided. The Linux system includes a memory, a system on a chip (SoC) device, and a first circuit. The SoC device includes the memory and is programmed to process at least a reference signal indicative of undesired audio content and a measured signal indicative of measured audio data in a listening environment. The first circuit is programmed to receive the reference signal and the measured signal. The first circuit is further programmed to merge the reference signal with the measured signal to provide a combined system input to the SoC device to prevent temporal misalignment between the reference signal and the measured signal caused by one or more software layers of the Linux system.

An audio signal processing method implemented by an audio system with an audio sensor and a speaker unit includes: measuring, by the audio sensor, acoustic signals reaching the audio sensor, producing a sensor audio signal; retrieving a speaker audio signal corresponding to a speaker acoustic signal from the speaker unit while measuring the acoustic signals reaching the audio sensor to produce the sensor audio signal; converting the speaker and sensor audio signals to speaker and sensor audio spectra; estimating, based on the speaker audio spectrum, an echo audio spectrum of an echo audio signal caused by the speaker acoustic signal in the sensor audio signal; computing, based on the echo audio spectrum and the sensor audio spectrum, echo suppression gains to be applied to the sensor audio spectrum, by using a MMSE-LSA estimator; and applying the echo suppression gains to the sensor audio spectrum.

A method for echo cancellation based on microphone signal correlation is disclosed. The method includes replaying a reference signal by a speaker; collecting a primary audio signal by a primary microphone and a secondary audio signal by a secondary microphone based on the reference signal being replayed; partitioning the reference signal into a plurality of sectioned reference signals, based on levels of correlation between the primary audio signal and the secondary audio signal; generating a plurality of sectioned primary echo signals for the primary microphone by processing the sectioned reference signals by an acoustic audio canceller (AEC); generating a plurality of sectioned secondary echo signals for the secondary microphone by processing the sectioned reference signals by a predictive acoustic audio canceller (AEC-P), wherein the AEC-P generates at least one of the sectioned secondary echo signals based on a corresponding sectioned primary echo signal; and performing echo cancellation for the secondary microphone by removing a combination of the sectioned secondary echo signals from the secondary audio signal.