Your problem may be related to the fact that you are using an imported MIDI file with microchords. Thus the bass track was not generated with the microchords and not in sync with it. I have found that the microchord feature to be a PITA at times.

Have you tried to let BiaB generate a bass line? You might be able to generate said track and in the piano roll view carefully arrange the notes to match your bass lines.

Have you tried to convert your bass line to an MP3 and incorporate it in BiaB or maybe even better RealBand or any other DAW. That is convert the BiaB sans the bass and merge that MP3 with your bass MP3 in a DAW. YMMV


The fitness trainer asked me, "What kind of a squat are you accustomed to doing?" I said, "Diddly."


64 bit Win 11 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware