The only thing I dont like about speed controllers is that with some fans it makes them even LOUDER believe it or not. It can cause some fans to emit a loud buzzing electrical noise thats louder than the air noise. Only when you use the variable setting though. My experience is with a Speedster controller btw.

I bought and sold a few different brands of fans until I found a brand that doesnt do the buzz. I use Eco plus fans and they are quiet. no buzz either from the controller. Never tried a Vortex because they were alot more than all the others but from some of the CFM ratings on them im sure they can be loud as shit.

Had a 10" fan from a brand that started with a D... cant remember name... Shit was so loud I would get nervous letting it spin up to full RPM lol.
Best bet is to build a box around it.