-you need 2 saw waves (or more, even 4 could do it)
-detune them as much as you can without making it completely sound out of tune
-distort the other (just a teeny bit) or then add some of that fractal effect to make it sound crisp if you want
-add a bandpass filter or if you happen to have absynth then use the comb filter, and make the filter frequency shiftaround 300-600
made exactly like this it sounds a bit harsh but gives the right direction.