I know its easy to pick fast with 3-note string(going down)...but how do u do it with 4-note or 2-note per strings....wen u pick 3-note per string its down up down, down up down, but with 2-notes per string its down up down up, and i cant get any speed at all, is there another technique or something?
no... you do go down and up... you just have to be able to syncronize your fret hand with your picking... thats all
When doing 3 notes per string, I believe it makes more sense to do straight alternate picking......down up down, up down up, etc.. It is the same with any set of notes, its just a matter of synchronization, as people have already said.