How can you stop the dimmer switch from causing the loud ringing noise when it is engaged?

Ringing Noise? Heard of buzzing noise from the light bulbs. Buzzing can be caused by the dimmer's pulsesation. This can be corrected by using a better quality filament bulb. If the bulb is replaced, and you still get the buzz, then try a new dimmer.
I've never heard of dimmer ringing when switched?
Interesting!
Sounds defective. Question: Do you have any fluorescent lights on this dimmer, or on the same circuit?