One of the great features of recessed LED lighting is the ability to dim the lights.
While most LED lights are dimmable, a common complaint is hearing a buzzing sound coming from the lights when they are dimmed.
The cause is almost always a compatibility issue between the dimmer and the LED’s driver (power supply). LEDs are electronic devices, and using a dimmer that was designed specifically for the resistive load of an incandescent lamp will seldom work well.
Most manufacturers now provide a list of recommended dimmers that they have tested to be compatible with their products. Of all the dimmers on the list, there are two types to look for that will likely work best at eliminating the buzzing.
What you’re looking for is either a CL dimmer or an ELV dimmer.
CL dimmers are made by Lutron and designed to be compatible with LEDs. My experience with them has been excellent. They have a low-end trim adjustment that allows you to get the best dimming range possible. CL dimmers will eliminate the buzzing on most brands of LEDs, but not all.
Electronic Low Voltage (aka reverse phase or trailing edge) dimmers are designed for electronic (capacitive) loads like LEDs. In my experience, ELV dimmers have eliminated the buzz every time.
Note: ELV dimmers require a neutral wire in the box.