Numbers 1 and 2 define the order of the tracks in the output file. Our free online audio joiner allows you to join your audio files into one. The Launchpad app comes free with eight ready-to-play sessions, and additional sound packs and features such as audio import are available as in-app purchases. Your friends vote songs up to the front of the line. edjing Pro could be one of the more attractive options for those who DJ with a smartphone or tablet. Free to use, the app also facilitates keeping the merged and trimmed files on separate storage path. App to mix songs together free With this music mixing application, you can make your own music, record a podcast, mix songs, and many more.