Occult noise and the pulse of sanity

An undiscoverable hum has been haunting my second story listening room for two weeks.  I powered down AND unplugged separately my active speakers, then my preamp, then my DAC to no avail.  The hum persisted as I tracked what surely must be a dying transformer in some piece.  The sound very diffuse and steady.

Alas, the ceiling fan running just below the listening room was discovered to be the culprit.  Although a quality Minke fan, it nonetheless generated enough hum to transmit and make me crazy.  Hope this helps anyone else bird dogging this kind of noise transmitted through framing and flooring.

By the title of your thread I thought I'd be reading about how you had to hire a medium to suss out whatever specter or apparition was to blame.

Nice way to catch eye balls.

All the best,
So if I have a mystery hum in my listening room it’s coming from your ceiling fan??
 I believe I had this same problem in my last house.
Also, I lived in a huge apartment complex which had massive electrical transformers directly behind my bedroom wall.
I actually had the electric company take readings to make sure
I wasn't sleeping in a huge magnetic field.
You can't be too careful...
Do you believe the hum was caused by the EM fields radiating out from the fan motor or from noise getting into the AC mains? For those of us with radon fans that run all the time, are we better off switching those fans off during listening sessions?
Just low level motor hum amplified by the wood framing it is attached to.  Nothing nefarious here.  Simply annoying and readily remedied.