Is a dimmer noisy when it's turned OFF?

Friends, my wife wants to add a rheostat to the dining room ceiling lamp. I know that dimmers are big sources of electrical noise, could will it have any effect on my listening room power when it's turned completely off? Just want to be sure.
Good description. We also get that effect from leaving various appliances plugged in (microwave oven, television, etc.) even when they're switched "off". It's pretty low level, but for insanely critical listening we unplug as many as we conveniently can.
Zero crossing dimmer is key. Cheap dimmers cause all kinds of noise. Here is what I learned posted in a non audiophile forum...

Wouldn't the key be to have lighting and dimmer on a separate circuit or even a different sub panel? I use dimmers in my home theater/listening room to great effect and notice no problems with noise. My components do run from a separate sub panel though. To me the right level of lighting can make all the difference, hard to control without dimmers.
Sonofjim, I my dimmers and have zero interference that I can detect.
06-05-13: Sonofjim
Wouldn't the key be to have lighting and dimmer on a separate circuit or even a different sub panel?
That certainly can't hurt, and certainly may be helpful. But I wouldn't count on it as being any kind of guarantee. There are too many variables involved that have essentially no predictability, including the possibility that radiated RFI may couple through the air to sensitive circuit points within the components and intermodulate with the audio signal, the run lengths and physical routing of the house wiring, the sensitivity of the particular components to distortion of the AC waveforms they receive, and of course the characteristics of the particular dimmers.

I mentioned earlier that I have no dimmers in my house. I do have, however, a floor-standing fluorescent lamp that has a built-in continuously variable dimmer (which is not in my listening room, and is almost always turned off). I just did an interesting experiment with it. I have a battery-powered portable transistor radio that can receive long-wave frequencies (below the AM broadcast band) down to about 140 kHz. I set it to that frequency, and to a volume control setting in the lower part of its range, and positioned it about 10 feet from the lamp. As I varied the setting of the dimmer on the lamp I heard nothing through the radio at most settings. However at a small range of settings corresponding to a moderate amount of dimming, the radio produced noise approaching the volume levels at which I would normally listen to radio stations on that set.

-- Al