Dimmer causing buzzing

[kriminaal]

I'm installing some dimmer switches and have a floodlight installed in one.
However there is a buzzing at every turn unless it is full on or off.

Is it an improper bulb type that is causing this?
Or do I have it wired incorrectly.
I have it wired hot to hot
neutrals bypass dimmer
3 grounds together

thanks

[HayZee518]

the wiring is correct. the dimmer electronics create a square wave instead of a pure sinusoidal waveform. the output device is called a triac and it is gated [turned on and off] via electronics on its control board. they make an anti buzz coil but its a little pricey at $160 each!