Sweepers are used to avoid interrupting a song playing before an event starts. For instance, a song starts to play but after 20 seconds there's a scheduled event that is about to start. The event will interrupt the song. To avoid this situation, RadioBOSS can insert a sweeper, in this case, a 20-second sweeper will play instead of the song and then the event will start.
To assign a sweeper: in the event window, Click the "Sweepers..." button and select a folder with sweepers. The more sweepers with different durations the folder contains, the better.
There are repeat protection rules for sweepers, to open the repeat protection settings, click the "Repeat protection" button in the sweepers window, or use the Playlist -> Extra -> Sweeper repeat protection menu command. Repeat protection settings are common for all sweepers.
Sweeper selection quality can be controlled in the settings in the Scheduler section.