For the parents ( as me) that they want to listen music with their children my advice is to go to the pop festival nuremberg. It is really nice there are different bands and it is comfortable to go with children. http://www.nuernberg-pop.de/festival/
For the children it was fun, they dance a lot’s , they saw different type of instruments and they really enjoyed. There are several places where you can listen music with them, but my advice is to go the New Museum because there is a lot’s of space for them to play and to dance.