Did you try this syntax:
ARTIST MATCHES [\x{0000}-\x{007F}]
(I don't know what the range \u0000-\u007F should include, maybe you can explain what do you like to filter? Do you mean all this characters
inlcuding all the control chars?
Or do you mean filter everything except "a-zA-Z0-9äöüàéèÄÖÜ?")