A progress bar could work for the 'unfolded' mode, where the song plays from bar#1 until the end.
In 'folded' mode, we have to know, at every time, where we are in the song sequence, mainly when we have several chorus. If we have only two chorus, that is not very difficult to remember it. When you have 3,4,5 ... and more chorus, we need a visual mark of the chorus number being played not only a progress bar.


Reach for excellence