In any case, when a VAS receives detected sound data, the VAS will typically process this data, which involves identifying the voice input and determining an intent of words captured in the voice input. The VAS may then provide a response back to the NMD with some instruction according to the determined intent. Based on that instruction, the NMD may cause one or more smart devices to perform an action. For example, in accordance with an instruction from a VAS, an NMD may cause a playback device to play a particular song or an illumination device to turn on/off, among other examples. In some cases, an NMD, or a media system with NMDs (e.g., a media playback system with NMD-equipped playback devices) may be configured to interact with multiple VASes. In practice, the NMD may select one VAS over another based on the particular wake word identified in the sound detected by the NMD.
In some implementations, a playback device that is configured to be part of a networked media playback system may include components and functionality of an NMD (i.e., the playback device is “NMD-equipped”). In this respect, such a playback device may include a microphone that is configured to detect sounds present in the playback device's environment, such as people speaking, audio being output by the playback device itself or another playback device that is nearby, or other ambient noises, and may also include components for buffering detected sound to facilitate wake-word identification.