Minimuim voltage for case fan

samqweqwe

Honorable
Jan 1, 2013
65
0
10,630
hello,
i have a few of the cool master SickleFlow 120mm fan. I find that the fans are very loud so i decided to buy a speed reduction cable (a resistor on a wire for a fan). I already have the aero cool F6XT fan controler but it does not make the fans go quiet enough.
Question: what is the lowest operational voltage for the cool master fan?