1. A method comprising: receiving, by a computing device and from a user-input device, a request for content; in response to determining that the request for content does not specify a particular location for receiving the content, determining whether the user-input device is co-located with a content-outputting device having a first location by: determining, by the computing device, audio content being transmitted to and output by the content-outputting device; transmitting, by the computing device and to the user-input device, a request for the user-input device to capture audio content detected by the user-input device; receiving, by the computing device and from the user-input device, the audio content detected by the user-input device; comparing, by the computing device, the audio content detected by the user-input device with the audio content being transmitted to and output by the content-outputting device; and in response to determining that the audio content detected by the user-input device matches, within a similarity threshold, the audio content being transmitted to and output by the content-outputting device, determining that the user-input device is co-located with the content-outputting device at the first location; and in response to determining that the user-input device is co-located with the content-outputting device at the first location, causing transmission of the content to the content-outputting device.