This is a small app about DJ Sona, which let's you loop her tracks (Kinetic, Concussive and Ethereal), including the transitions.
This app uses the assets used by Riot on the login screen, during DJ Sona's launch, which are not made available publicly through this repository.
More details and download links available on this reddit post: https://www.reddit.com/r/leagueoflegends/comments/3fr8wy/ive_made_a_dj_sona_desktop_app_for_looping_her/