Hi Finaly found out where the strange radiolike noises came from..  When I bought me two studio-monitors I hooked them up with remote-controlled power outlets.. and then I had a splitter for my big stereo speakers. So I can switch back and forth from the two speakersets. 2-3 years with strange old radio interfense-like sounds aspecialy when I play loud trew my headphones. I started to investigate the settings in my soundcard but couldn't find anything. 
A week ago I decided to sell my studio-monitors and removed those two remote controlled power outlets and the radionoise was gone!!!    Those remote control power-outlets is comunicating with a radio signal which then lead the the constant noise problem I had.