Abstract: Some implementations involve obtaining a plurality of echo references, the plurality of echo references including at least one echo reference for each audio device of a plurality of audio devices in an audio environment, each echo reference corresponding to audio data being played back by one or more loudspeakers of one audio device of the plurality of audio devices. Some examples involve making an importance estimation for each echo reference of the plurality of echo references. Making the importance estimation may involve determining an expected contribution of each echo reference to mitigation of echo by at least one echo management system of at least one audio device of the audio environment. Some implementations involve selecting, based at least in part on the importance estimation, one or more selected echo references and providing the one or more selected echo references to the at least one echo management system.

Abstract: Some implementations involve receiving location information for each of a plurality of audio devices in an audio environment, generating, based at least in part on the location information, rendering information for a plurality of audio devices in an audio environment and determining, based at least on part on the rendering information, a plurality of echo reference metrics. Each echo reference metric may correspond to audio data reproduced by one or more audio devices of the plurality of audio devices. The rendering information may include a matrix of loudspeaker activations. Some examples involve making, based at least in part on the echo reference metrics, an importance estimation for each of a plurality of echo references, selecting, based at least in part on the importance estimation, one or more echo references and providing them to at least one echo management system for canceling or suppressing echoes.

Abstract: An attenuation or “gap” may be inserted into at least a first frequency range of at least first and second audio playback signals of a content stream during at least a first time interval to generate at least first and second modified audio playback signals. Corresponding audio device playback sound may be provided by at least first and second audio devices. At least one microphone may detect at least the first audio device playback sound and the second audio device playback sound and may generate corresponding microphone signals. Audio data may be extracted from the microphone signals in at least the first frequency range, to produce extracted audio data. A far-field audio environment impulse response and/or audio environment noise may be estimated based, at least in part, on the extracted audio data.

Abstract: Some methods may involve receiving a first content stream that includes first audio signals, rendering the first audio signals to produce first audio playback signals, generating first direct sequence spread spectrum (DSSS) signals, generating first modified audio playback signals by inserting the first DSSS signals into the first audio playback signals, and causing a loudspeaker system to play back the first modified audio playback signals, to generate first audio device playback sound. The method(s) may involve receiving microphone signals corresponding to at least the first audio device playback sound and to second through Nth audio device playback sound corresponding to second through Nth modified audio playback signals (including second through Nth DSSS signals) played back by second through Nth audio devices, extracting second through Nth DSSS signals from the microphone signals and estimating at least one acoustic scene metric based, at least partly, on the second through Nth DSSS signals.

Abstract: Some methods may involve receiving a first content stream that includes first audio signals, rendering the first audio signals to produce first audio playback signals, generating first direct sequence spread spectrum (DSSS) signals, generating first modified audio playback signals by inserting the first DSSS signals into the first audio playback signals, and causing a loudspeaker system to play back the first modified audio playback signals, to generate first audio device playback sound. The method(s) may involve receiving microphone signals corresponding to at least the first audio device playback sound and to second through Nth audio device playback sound corresponding to second through Nth modified audio playback signals (including second through Nth DSSS signals) played back by second through Nth audio devices, extracting second through Nth DSSS signals from the microphone signals and estimating at least one acoustic scene metric based, at least partly, on the second through Nth DSSS signals.

Abstract: Some implementations involve receiving, from a first subband domain acoustic echo canceller (AEC) of a first audio device in an audio environment, first adaptive filter management data from each of a plurality of first adaptive filter management modules, each first adaptive filter management module corresponding to a subband of the first subband domain AEC, each first adaptive filter management module being configured to control a first plurality of adaptive filters. The first plurality of adaptive filters may include at least a first adaptive filter type and a second adaptive filter type. Some implementations involve extracting, from the first adaptive filter management data, a first plurality of extracted features corresponding to a plurality of subbands of the first subband domain AEC and estimating a current local acoustic state based, at least in part, on the first plurality of extracted features.