>> I only want to generate the bass part to performance tracks

Yes, you could do that as follows:

1. Mute all tracks except bass (right click on bass, and choose solo)
2. Load a song from the desired folder
3. Batch render (press WAV button, and then the Batch button inside the dialog.
In the batch dialog, set the Suffix to " Bass", and choose WMA, and press GO.

The batch will proceed, take about 30 seconds per song.

4. When you're done, erase the WAV files that were created (when it creates WMA, it also creates WAV) by selecing them all in explorer and deleting them.

You're done, in 4 steps.

Have Fun!
Peter Gannon
PG Music Inc.