which fans speed controller do i need to avoid vibrations?

i kno theres a certain controller that stop vibrations coming from within the fan but which is it ?

soo...a fan controller that detects vibration...sounds like a load of horse shit to me, or REALLY fucking expensive...

reduced speed = reduced vibration, all fan controllers are capable of this...
smoother bearings reduces vibration...
equally balanced fan blades = reduced vibration...
rubber bungee cords to absorb the vibration?

Dunno what to tell you..i've never heard of such a fan controller...

it doesnt detect vibration wot woud be the point in that, i dont kno how it works but i heard people talkin about acertain modle being renowned for less vibration coming fromthe fan when usiing this certain type of controller, do you use a controller?

I read the other post you started regarding this topic where someone said it needed to use a variac transformer...that honestly has nothing to do with vibration. A variac based fan speed controller just uses more expensive parts(i.e. the variac)...it provides cleaner electricity to the motor yes, but you are not going to see any difference in vibration due to the usage of it. You'll be able to more smoothly control the fans speed, but thats the reason its more expensive. Like I said in my upper post here, the higher quality the fan, the higher the quality of the bearings will be, and the more true the blade balance will be. That's where you get your vibration from any fan.

If a product exists where you put sensors on the outside of a fan to measure how much its vibrating and in turn reduce the amount of voltage applied to the fan(which they do exist, but require alot more money and its more for industrial applications where vibration causes an issue with some manufacturing process so the speed is reduced to compensate and controlled), you are still reducing the RPM's, reducing air flow, which can still be done with a cheap analog dimmer switch...

If you want to go and spend thousands of dollars just to have your fans automatically throttle itself back to reduce vibration more power to ya man...but I'd recommend just getting a higher quality balanced fan and use dampening technology like rubber standoffs/bungee cords/etc...any manufacturer that says their fan controller reduces vibration when you are only hooking up two wires to the AC fan is giving you a line of horse shit...