Cheers for your advices but I've already tried all that things. first thought that's just on the peaks but found than out that it is a generally frequency problem on all harmonics. So tried to turn it out on every one but the only thing which happend was that the sample sounded like shit and the squeaking noise was still there.
I'm not really into violins and instruments like this one (I'm a classic computerbased musician
), , so that I think that it could be that I tried to play it higher than it's possible on a real instrument.
at the end, I played the same thing once on one octave and once on two octaves deeper, tried to get a good mix beetween dark and squeaking, packed a cool trombone and e-grand in my track and called it "schizophrenic orchestra".......
....know it's not that bad like before when I thought it's gonna kill my ears.
maybe I'll upload it soon. would be nice to get a feedback because it's actualy my first track with "real" instruments instead of modulated synths.