any speed control gadget compatible with your average clip fan?

Is there a safe way to incorporate some method of speed control with your average clip fan? i have a Holmes HACP10B-U Oscillating Clip Fan.
low is just a touch too loud for this cab. i would like to stick with this one. not ready to jump to 120mm's just yet

More than what the fan probably costs itself

Im guessing its AC? Lil voltage dimmer pot @ 120V will do. If it is DC, then a Linear Pot is the way to go.

AC fan
i have read a couple places that it may be a hazard to run with a dimmer, but i find that hard to believe. Im a former contractor and wonder how its not a hazard to install these on bath fans etc. i know its an obvious solution but reading a contrary position in a few places on the net gives me pause. btw-first timer and i'm running a 2'x6'x42" veg cab. with a panasonic whisper green pulling air, replaced and raised the fans on my 3 hans panels.

the holmes gives me a little low end hum when the doors are closed. it's very quiet but i can do better to be absolutely undetectable.

can bending the blades either flatter or more concave reduce the small vibrations?

thx for replying

ahh i was over thinking it. i ended up getting a "speedster" controller. should do the trick

FYI the speedster wasnt the way to go. i bought a variac controller and that gives me a full smooth range of low to high speeds. this is the way to go.