Hey Notes,
thanks for the link! I've already read somewhere about these books, but didn't have a link yet resp. haven't managed to search for it yet. What I've also read before is that they are without melodies and lyrics and therefore don't violate copyrights. Can you confirm that?
You are correct. No melodies or lyrics. Some of the copyright holders refused, others wanted to charge up to $2.50 per song.
So the compromise I made was to make fake disks with off-the-shelf music books. That way you can open the BiaB file, open the page in the book with the melody, click "play" and play along with the track by reading the melody line in the book.
I put a link to the book in the same page as my fake e-disk. The link is to Amazon, but you can also get the book elsewhere.
Notes ♫