The advice that separate lines solves the problem is incorrect. Since all of the lines are tied together at the breaker box even if the dimmer is on the other hot phase they share a common neutral line so they are not isolated. I had a dimmer on the stove hood in my kitchen which caused my stereo to buzz in the basement and the stereo was on a different breaker. However, I do agree that modern dimmers are not a problem. I have one on almost every wall switch in my house as well as several lamps with built in dimmers and I have no noise.
How do you do that?
.
When we create media rooms we always isolate the lines in a manner that eliminates line interference.
How do you do that?
.