Adobe Captivate: Methods for Attaching Voiceover Audio
The Logical Blog by IconLogic
FEBRUARY 7, 2013
However, I wouldn't use this technique for voiceover audio. Background-level audio is perfect for background music. Personally, I think background music will quickly becomes a distraction (perhaps even an irritant) for your learners, which is why I shy away from it. As for voiceover audio, I don't recommend that you add it to a project as the background.