For multiple audio tracks and mixing of such you may want to look at Realband. This comes free with BiaB and is a more conventional DAW based software with 48 tracks that can be either MIDI or audio. It also supports the song generating features of BiaB.

Your audio track should be near the bottom of the BiaB mixer applet I believe.


I do not work here, but the benefits are still awesome
Make your sound your own!