background audio

In Captivate 4, I would like to import an mp3 file as background music on a project originally transferred over from a PowerPoint presentation.

The project includes voiceover on about 80% of the slides (added the voiceover after uploading to C4).

When a slide transitions from one to another, I notice the background music is too loud until the voiceover starts on the slide. then, once the voiceover completes, the bg music becomes way too loud again...I did notice that there is a choice on the slides to control the volume if voiceover is on the slide...

I was wondering if there is a way to have the background mp3 music stay at a constant lowered volume level without the increase/decrease if and when a voiceover addition occurs on a slide? I don't care if the voiceover drowns the background music out...think it sounds much nicer at a constant level.

Thanks in advance!