A method for estimating a user's location in an environment may involve receiving output signals from each microphone of a plurality of microphones in the environment. At least two microphones of the plurality of microphones may be included in separate devices at separate locations in the environment and the output signals may correspond to a current utterance of a user. The method may involve determining multiple current acoustic features from the output signals of each microphone and applying a classifier to the multiple current acoustic features. Applying the classifier may involve applying a model trained on previously-determined acoustic features derived from a plurality of previous utterances made by the user in a plurality of user zones in the environment. The method may involve determining, based at least in part on output from the classifier, an estimate of the user zone in which the user is currently located.

An audio cancellation system includes a voice enabled computing system that is connected to an audio output device using a wired or wireless communication network. The voice enabled computing device can provide media content to a user and receive a voice command from the user. The connection between the voice enabled computing system and the audio output device introduces a time delay between the media content being generated at the voice enabled computing device and the media content being reproduced at the audio output device. The system operates to determine a calibration value adapted for the voice enabled computing system and the audio output device. The system uses the calibration value to filter the user's voice command from a recording of ambient sound including the media content, without requiring significant use of memory and computing resources.

Acoustic waveguides can be used to improve audio performance of playback devices, such as a soundbar. Such a playback device can include an elongated body defining an outer perimeter with a forward surface, an upper surface, and a rounded edge between the forward surface and the upper surface. An up-firing transducer is configured to direct sound along an axis that has a vertical oblique angle with respect to a forward axis. A waveguide in fluid communication with the up-firing transducer includes a sidewall extending circumferentially around the transducer, the sidewall having a first end adjacent the up-firing transducer and a second end adjacent the outer perimeter, such that an opening defined by the sidewall has a larger area at the second end than at the first end. A rear portion of the sidewall is more steeply angled with respect to the axis than a forward portion of the sidewall.

Systems, methods, and apparatus for frequency routing based on orientation are disclosed. An example method includes receiving, by a playback device, an audio data stream. The example method includes determining, by the playback device, an orientation of the playback device. The example method includes routing, by the playback device, a first set of frequencies in the audio data stream to at least one of a plurality of speaker drivers based on the first orientation. The example method includes routing, by the playback device, a second set of frequencies in the audio data stream to the at least one of the plurality of speaker drivers based on the second orientation, wherein the first set of frequencies is different than the second set of frequencies.

Example techniques may involve guest access to a media playback system. A guest may use a guest control device, such as a smartphone or tablet, to control aspects of a host’s media playback system. In addition, the guest may temporarily register their user account of a streaming audio service with the host’s media playback system, which enables playback of audio content from that service by one or more playback devices of the media playback system. When the guest control device de-registers from the host’s media playback system, retrieval of audio content from the streaming audio service is disabled.

Systems and methods for use in a media playback system comprising one or more playback devices are disclosed, where a playback device has a corresponding first set of device attributes used by a first controller application. The methods include: (i) identifying a second set of device attributes used by a second controller application to control the playback device, (ii) selecting a second device attribute for the playback device from the second set of device attributes based at least in part on a first device attribute; (iii) storing the selected second device attribute in the first set of device attributes; and (iv) controlling at least one function of the playback device using the selected second device attribute.

A playback device is configured to: produce a first channel audio output of a first channel of audio content; produce a second channel audio output of a second channel of the audio content; receive captured audio content comprising (i) a first portion corresponding to the first channel audio output, (ii) a second portion corresponding to the second channel audio output, and (iii) a third portion corresponding to a voice command, wherein the captured audio content has a first signal-to-noise ratio; determine a set of signal components from at least one of the first channel or the second channel of the audio content; perform acoustic echo cancellation on a subset of signal components; determine an acoustic echo cancellation output; and apply the acoustic echo cancellation output to the captured audio content and thereby increase the first signal-to-noise ratio to a second signal-to-noise ratio that is greater than the first signal-to-noise ratio.

A method for selectively transmitting audio signals in a fire alarm system includes receiving, by a Notification Appliance Circuit (NAC) selecting device, an audio signal for transmission over a first NAC or a second NAC. Each of the first NAC and the second NAC includes respective groupings of one or more NAC appliances. The NAC selecting device receives a selection signal from a Fire Alarm Control Panel (FACP) electronically connected to the NAC selecting device. The selection signal identifies one or more NAC appliances that should be moved from a first grouping corresponding to the first NAC to a second grouping corresponding to the second NAC. The NAC selecting device selectively transmits the audio signal to one of the first NAC and the second NAC based on the selection signal.

Example techniques involve controlling playback volumes. An example implementation includes displaying a group volume control of a synchrony group, the group volume control comprising a group volume indicator on a group volume slider and receiving, via the displayed group volume control, input data representing a selection of the group volume control. The implementation also includes displaying, concurrently with the group volume control, a first volume control comprising a first volume indicator on a first volume slider and a second volume control comprising a second volume indicator on a second volume slider. The implementation also includes receiving, via the displayed group volume control, input data representing an input to modify a first volume setting of the synchrony group to a second volume setting and transmitting instructions to cause the synchrony group to modify volume settings according to the second volume setting of the synchrony group.

Techniques for controlling zone group and zone group characteristics such as audio volume in a multi-zone system are disclosed. The multi-zone system includes a number of multimedia players, each preferably located in a zone. A controller may control the operations of all of the zone players remotely from any one of the zones. Two or more zone players may be dynamically grouped as a zone group for synchronized operations. According to one aspect of the techniques, a zone group configuration can be managed, updated, modified via an interactive user interface provided in a controlling device. The zone group configuration may be saved in one of zone players. According to another aspect of the techniques, the audio volume control of a zone group can be performed individually or synchronously as a group.