Noise + Noise = No Noise ?

[Waldoman]

I’m wondering if anyone has a technical explanation as to why the following occurred.

I have an x-10 light switch operating that was supposed to be operating a lamp. The switch is on the same circuit as a noisy TV that even a filter did not help. I could never turn the lamp on or off, other than manually with the switch, if the TV was plugged in.

Recently I purchased another computer that was creating noise on another circuit so I decided to move the computer to the circuit with the noisy TV. I thought it might be better just to have one light not working.

Much to my surprise the light that is now on the circuit with the noisy TV and noisy computer works perfectly.

I know that noise is not additive but I also didn’t think that one noise source could cancel another source. Any explanation ?

[Scottbee]

I'm going to guess that one of them isn't actually a noise source, but a "signal sucker"... which is somewhat common.

Sometimes when you put a signal sucker on the same circuit as a noise source, the "sucker" eats the noise. Hard to believe, but true.

You probably won't know the real story unless you get a line analyzer.

[wpiman]

Hmmm- did you have to plug in a power strip to allow the TV and the computer to use a single socket by chance?

[Jim Doolittle]

I read about some company who came up with a way of monitoring sound and creating the same sound only 180° out of phase. The result was silence. Weird.

Jim Doolittle

[jacw]

They work pretty well, better on low frequency sound than high frequency sounds though.

[Waldoman]

I suppose I can understand a “signal sucker” canceling out the noise but then I would think it would have eaten up the X10 signal also. I don’t use any repeaters. Different frequency maybe.
No power strip just a different outlet on the same circuit.
Oh well, maybe I just need to start keeping a log of what I can unplug and what I can’t.