In some embodiments, one or more of the playback devices 102 may include an on-board (e.g., integrated) network microphone device. For example, the playback devices 102a-e include corresponding NMDs 103a-e, respectively. Playback devices that include network microphone devices may be referred to herein interchangeably as a playback device or a network microphone device unless indicated otherwise in the description.
In some embodiments, one or more of the NMDs 103 may be a stand-alone device. For example, the NMDs 103f and 103g may be stand-alone network microphone devices. A stand-alone network microphone device may omit components typically included in a playback device, such as a speaker or related electronics. In such cases, a stand-alone network microphone device may not produce audio output or may produce limited audio output (e.g., relatively low-quality audio output).