User-defined media source synchronization

Within environments, such as audio-video environments, users may synchronize output of multiple media source(s). To synchronize the output of the media source(s), users may define setting(s) associated with outputting the media source(s) at one or more devices. For example, the user may delay or accelerate the output of audio and/or video sources. Interfaces presented on one or more of the devices may allow the user to change the settings. For environments including multiple users, each user may define setting(s) associated with each user to synchronize output of their associated media source(s). Recommendations may be provided to users, that when implemented, attempt to synchronize the media sources.