Originally Posted by Kaleb.G
Yeah, that's true. Vocal tracks may be a bad idea, unless it's a vocal-heavy album. However, you could always crank the volume lower on stuff like this.
Another tip is to use an equalizer to cut away the vocal frequencies from a track (reduce around 5khz) to let your voices go through more. That's a bit technical though, I recommend just keeping the volume down and choosing less busy tracks for background music.