Abstract: Example techniques involve balancing bass response of a multiple driver playback device. An example playback device receives left and right channels of audio content and generates a center channel of the audio content by combining at least a portion of the left right channels. The playback device generates first and second side channels of the audio content by combining the center channel and a difference of the left channel and the right channel and combining the center channel and an inverse of the difference of the left channel and the right channel, respectively. The first and second side channels are attenuated by a filter with a given cutoff frequency. The center channel is amplified in proportion to the attenuation of the first side channel. The playback device plays back the first side channel, second side channel, and center channel according to respective radiation patterns having maximums aligned in respective directions.

Abstract: Systems and methods for three-dimensional beamforming disclosed herein include, among other features (i) generating a set of received-sound beams by applying a plurality of sets of beamforming coefficients stored in a tangible memory of the network device to sound received via a microphone array of the network device, wherein each received-sound beam corresponds to a separate direction relative to the microphone array, (ii) identifying a subset of the received-sound beams comprising speech content, (iii) for each received-sound beam in the subset of the received-sound beams comprising speech content, determining whether the speech content comprises a wake word, (iv) selecting one final received-sound beam from the received-sound beams in the subset of the received-sound beams determined to comprise a wake word; and (v) causing the selected one final received-sound beam to be processed to identify a voice command.

Abstract: A method of operating a playback device includes receiving source audio content that includes a first and second channel stream of audio. The method also includes playing back, via a first and second speaker driver of the playback device, the first and second channel streams of audio, thereby producing a first and second channel audio output. A captured stream of audio is received by a microphone of the playback device, and portions of the captured stream of audio correspond to the first and second channel audio outputs. The first and second channel streams of audio are combined into a compound audio signal, and acoustic echo cancellation is performed on the compound audio signal to produce an acoustic echo cancellation output, which is then applied to the captured stream of audio to increase the signal-to noise ratio of the captured stream of audio.

Abstract: Disclosed herein are example techniques to provide contextual information corresponding to a voice command. An example implementation may involve receiving voice data indicating a voice command, receiving contextual information indicating a characteristic of the voice command, and determining a device operation corresponding to the voice command. Determining the device operation corresponding to the voice command may include identifying, among multiple zones of a media playback system, a zone that corresponds to the characteristic of the voice command, and determining that the voice command corresponds to one or more particular devices that are associated with the identified zone. The example implementation may further involve causing the one or more particular devices to perform the device operation.

Abstract: Aspects of a multi-orientation playback device including at least one microphone array are discussed. A method may include determining an orientation of the playback device which includes at least one microphone array and determining at least one microphone training response for the playback device from a plurality of microphone training responses based on the orientation of the playback device. The at least one microphone array can detect a sound input, and the location information of a source of the sound input can be determined based on the at least one microphone training response and the detected sound input. Based on the location information of the source, the directional focus of the at least one microphone array can be adjusted, and the sound input can be captured based on the adjusted directional focus.

Abstract: Disclosed herein are example techniques for voice detection by multiple NMDs. An example implementation may involve receiving a set of voice recordings from a set of NMDs, and identifying a subset of voice recordings from which to determine a given voice command. The example implementation may further involve causing the identified subset of voice recordings to be analyzed to determine the given voice command.

Abstract: An example playback device receives left and right channels of audio content and generates a center channel of the audio content by combining at least a portion of the left right channels. The playback device generates first and second side channels of the audio content by combining the center channel and a difference of the left channel and the right channel and combining the center channel and an inverse of the difference of the left channel and the right channel, respectively. The first and second side channels are attenuated by a filter with a given cutoff frequency. When volume is adjusted, the cutoff frequency is adjusted based on the volume level of the playback device and the spectral characteristics of the audio content. The cutoff frequency is positively related to the volume level such that a volume increase causes a corresponding increase in the cutoff frequency and vice versa.

Abstract: An example playback device receives left and right channels of audio content and generates a center channel of the audio content by combining at least a portion of the left right channels. The playback device generates first and second side channels of the audio content by combining the center channel and a difference of the left channel and the right channel and combining the center channel and an inverse of the difference of the left channel and the right channel, respectively. The first and second side channels are attenuated by a filter with a given cutoff frequency. When volume is adjusted, the cutoff frequency is adjusted based on the volume level of the playback device and the spectral characteristics of the audio content. The cutoff frequency is positively related to the volume level such that a volume increase causes a corresponding increase in the cutoff frequency and vice versa.

Abstract: A signal from a sensor may be received indicative of an acceleration of a moving component of a transducer at a location where the sensor is mounted. A position the moving component may be determined based on the acceleration. The position of the moving component may be compared with a reference to output a measure of distortion associated with the transducer. Nonlinearities in audio output by the transducer may be corrected based on the measure of distortion.

Abstract: Disclosed herein are example techniques to provide contextual information corresponding to a voice command. An example implementation may involve receiving voice data indicating a voice command, receiving contextual information indicating a characteristic of the voice command, and determining a device operation corresponding to the voice command. Determining the device operation corresponding to the voice command may include identifying, among multiple zones of a media playback system, a zone that corresponds to the characteristic of the voice command, and determining that the voice command corresponds to one or more particular devices that are associated with the identified zone. The example implementation may further involve causing the one or more particular devices to perform the device operation.

Abstract: Example techniques relate to voice interaction in an environment with a media playback system that is playing back audio content. In an example implementation, while playing back first audio in a given environment at a given loudness: a playback device (a) detects that an event is anticipated in the given environment, the event involving playback of second audio and (b) determines a loudness of background noise in the given environment, the background noise comprising ambient noise in the given environment. The playback device ducks the first audio in proportion to a difference between the given loudness of the first audio and the determined loudness of the background noise and plays back the ducked first audio concurrently with the second audio.

Abstract: Aspects of a multi-orientation playback device including at least one microphone array are discussed. A method may include determining an orientation of the playback device which includes at least one microphone array and determining at least one microphone training response for the playback device from a plurality of microphone training responses based on the orientation of the playback device. The at least one microphone array can detect a sound input, and the location information of a source of the sound input can be determined based on the at least one microphone training response and the detected sound input. Based on the location information of the source, the directional focus of the at least one microphone array can be adjusted, and the sound input can be captured based on the adjusted directional focus.

Abstract: A first signal may be received indicative of audio to be played by a speaker. A second signal may be received which comprises (i) a voice input received by a microphone and (ii) at least a portion of the audio played by the speaker at a same time that the microphone receives the voice input. Based on the first signal, nonlinearities output by the speaker which played the audio may be determined. At least the nonlinearities from the second signal may be removed to output a third signal comprising substantially the voice input received at the microphone.

Abstract: Aspects of a multi-orientation playback device including at least one microphone array are discussed. A method may include determining an orientation of the playback device which includes at least one microphone array and determining at least one microphone training response for the playback device from a plurality of microphone training responses based on the orientation of the playback device. The at least one microphone array can detect a sound input, and the location information of a source of the sound input can be determined based on the at least one microphone training response and the detected sound input. Based on the location information of the source, the directional focus of the at least one microphone array can be adjusted, and the sound input can be captured based on the adjusted directional focus.

Abstract: An example playback device may identify a first version of audio content for play back from a first source, and further identify a first value of an audio characteristic of the first version of the audio content, where the playback device includes a capability corresponding to the audio characteristic. The playback device may determine that the first value of the audio characteristic of the first version of the audio content does not match the capability of the playback device. The playback device may then identify a second version of the audio content from a second source, where the second version of the audio content includes the audio characteristic having a second value that is closer to the capability of the playback device. The playback device may then cause playback of the second version of the audio content.

Abstract: Disclosed herein are systems and methods for receiving a voice command and determining an appropriate action for the media playback system to execute based on user identification. The systems and methods receive a voice command for a media playback system, and determines whether the voice command was received from a registered user of the media playback system. In response to determining that the voice command was received from a registered user, the systems and methods configure an instruction for the media playback system based on content from the voice command and information in a user profile for the registered user.

Abstract: Systems and methods for three-dimensional beamforming disclosed herein include, among other features (i) generating a set of received-sound beams by applying a plurality of sets of beamforming coefficients stored in a tangible memory of the network device to sound received via a microphone array of the network device, wherein each received-sound beam corresponds to a separate direction relative to the microphone array, (ii) identifying a subset of the received-sound beams comprising speech content, (iii) for each received-sound beam in the subset of the received-sound beams comprising speech content, determining whether the speech content comprises a wake word, (iv) selecting one final received-sound beam from the received-sound beams in the subset of the received-sound beams determined to comprise a wake word; and (v) causing the selected one final received-sound beam to be processed to identify a voice command.

Abstract: Aspects of a multi-orientation playback device including at least one microphone array are discussed. A method may include determining an orientation of the playback device which includes at least one microphone array and determining at least one microphone training response for the playback device from a plurality of microphone training responses based on the orientation of the playback device. The at least one microphone array can detect a sound input, and the location information of a source of the sound input can be determined based on the at least one microphone training response and the detected sound input. Based on the location information of the source, the directional focus of the at least one microphone array can be adjusted, and the sound input can be captured based on the adjusted directional focus.

Abstract: An example method includes receiving data indicating a configuration of one or more playback devices. The one or more playback devices may include one or more transducers. The method further includes, based on the received data, associating each of one or more audio streams respectively with at least one transducer of the one or more transducers. The method further includes generating the one or more audio streams and sending at least one of the generated one or more audio streams to each of the one or more playback devices. An example non-transitory computer readable medium and an example computing device related to the example method are also disclosed herein.

Abstract: Example techniques for acoustic position measurement in an example listening environment are disclosed. An example implementation involves a control device including a first transducer, a playback device including a second transducer, and a network microphone device (NMD) including a microphone array. The NMD determines a first direction of the control device with respect to the NMD based at least in part on a first test sound received at the microphone array from the first transducer and determines a second direction of the playback device with respect to the NMD based at least in part on a second test sound received at the microphone array from the second transducer. The NMD adjusts one or more beamforming parameters of the microphone array thereby causing amplifying sound received at the microphone array from the first direction and attenuating sound received at the microphone array from the second direction.