Add background soundtrack

MasterPlan, Apple Books, Thorium and Colibrio all have a nice feature, which strictly speaking is outside of the EPUB specification, to add an 'ambient soundtrack' to a book.

A background track plays when the reader is on the page, playing beneath any read aloud or other audio present. The track will loop and start playing again if it comes to an end.

Using the same track on adjacent spreads gives pleasantly uninterrupted audio that continues to play as the reader moves from spread to spread.

It is possible to have multiple soundtracks so changing the background audio and changing the mood for different sections of your EPUB.

To add one or more background soundtracks to a CircularFLO exported EPUB, click the Add background soundtrack button on the CircularFLO Read Aloud Tools panel to choose the audio track and add a small CircularFLO Soundtrack Panel to the pasteboard above your InDesign spread.

Tip: Hold down Command (Apple) key when using this tool to place the same soundtrack on every spread.