I've read through several threads now and haven't understand or found a way to fix my problem.
My original problem was, that the signal strength of my S4 Mini LTE (I9195) was way too strong, so that it interfered heavily with speakers in even 2m distance. I now think that I installed the Cyanogenmod Firmware without looking at the baseband version.
So now I'd like to know, if there was a way to get a fairly recent cyanogenmod (4.4.2 or later) with baseband version for Europe/Germany. (which i don't know)