A quick glance over your code suggest that the seq faults are caused by float functions that do not return anything. Try: fun float foo(){ return 0.0; //remember to return a float } The null pointer exceptions are propably caused by using SinOsc @ s[MAX_COMP]; This creates an array of null pointer SinOscs. Try without the @: SinOsc s[MAX_COMP]; -Pyry Pakkanen