Riing 120 RGB fan control

[deSenna24]

The View 28 RGB Riing edition came with one Riing RGB fan and a controller at the back that runs at constant 12V through molex, but is there a way to run the fan at a lower rpm and keeping the RGB? I saw some packs came with a controller but I can't find any seperate controllers to buy. I'm trying to just lower the rpm as the fan is just a bit too loud. I can't attach them to PWM headers on the motherboard as the fan uses a 5-pin instead of a 3 or 4-pin.