i like to add a little on your basic rock distortion type stuff. a lot of those type sounds just...i don't know how to describe it...they're just fuzzy, with high end fizz. kinda like a cottonball, with lots of tiny strands going every which way. compressing them seems to tighten them up, adding more definition. it also helps with the overall tonal color...i.e. less high-end frizz, and a more solid mid punch. that's the best way i could think to describe it. k