Originally Posted by Matt Finley
... even a florescent light can do this. ...
cheap LEDs can as well, they can add a lot of interference to various things
I had to solve that once by process of elimination; unplugged landscape lighting and issue went away
Luckily I didn't have to move to solve that one smile

But yeah, something in the house kicked on, as mentioned it could be furnace, A/C, Fridge .. I guessed furnace just because of your location <grin>

I do not work here, but the benefits are still awesome
Make your sound your own!