Hello Scott,
Thanks for your quick reply.
I have now downloaded the instructions in English. This is more detailed.
The German manual is unfortunately only as User Giude (Basics), there is no desciptiong of that.
The support of Casio answered my question like this: The Volumenknob does not affect the lineout signal. If they want the built-in speaker remains silent, they reduce the volume with Volumenknob. This of course does not work. I'll try with the settings and report. P.S: Do you have an idea why the Speaker remain active when using the lineout and for what type of application does this work/fit?