Example techniques related to a sub-index of a media index. An example implementation may involve maintaining, on a mobile device, a first index of audio tracks associated with a particular user profile, the audio tracks indexed in the first index consisting of a particular subset of audio tracks that are indexed in a second index. Based on the receiving the input data indicating the search query, the mobile device searches, within the first index, for audio tracks corresponding to the search query. If the audio tracks corresponding to the search query are not found in the first index, the mobile device sends to one or more servers of the cloud service, a request to search the second index for audio tracks corresponding to the search query.