Well, I have the same doubt about how to do a white noise/risers, and after a few days I achieve the sound what i was looking around (I work with FL Studio)
How i do a white noise:
1. In a project I open the Sylenth 1
2. I just select ¨noise¨ in wave (i just use the part A) (you can put it a little bit of cutoff)
3 . The in the mixer I open the Fruity Parametric EQ2 and put a High pass in the number one and adjust a little bit the other ones. (This makes the white noise more soft and less annoying)(Numbers are frequencies, I´m really not sure)
4. Do an automation clip in the pitch and adjust like you want
This white noise is soft and with the pitch automation makes it ´riser´
You can change the pitch replacing it for a cutoff automation clip (not the same effect on the sound)
Sorry for my bad english, is not my language