With Music Span, add-in you can play and loop a custom audio track across slides. You can play a single clip across slides or play different clips for each slide. Music span add-in will store the information within the presentation in the form of tags. This information is read during slide show and the relevant action is performed. If you have chosen to play a file, it will check for the presence of the audio file at that location and play. You can loop an audio file across slides or just a single slide. When a slide changes it checks for store settings, if it is unable to obtain them it performs the default action. Music span looks for the set audio at the specified location and if not found it will search in the presentation folder for them.