There are 3 types of audio files that PPRO
can produce audio lines for.
Stereo, Mono and 5.1
When you create your project, you can state how many of each you want. (You can also add and delete them from a project once you have started it)
You can only place Stereo, Mono and 5.1 audio clips in a track of the same type.
The tracks are identified by a single speaker icon for mono, A dble speaker icon for Stereo. and something for 5.1
Thank u very much!
This kind of thing is pretty well covered in the instructions (Help file). I'd recommend giving it a thorough read through.