What about an electrical transformer on a pole on the street? DH (an engineer) says he doesn't think telephone lines have enough current to hum.

I looked in the attic side and external wall and see no bee holes or bee activities.

The FiOS signal cable is fiber optic, not wire.

Inox, you are correct. For some reason we have the standard telephone (old tech) drop and it is hung on this side of the house. When they ran the FIOS, they also ran than off an overhead line too and that connects direct to the North side of garage. Could this possibly be the old (ran two years ago) cable line doing this? There are two lines from this side of the house and two near the garage, the thick being the power, the thin is the FIOS, I guess.

"Wind in the wires" aka the aeolian harp effect is commonly witnessed in wide open spaces. But I guess it could happen on the run of wires from the pole to the wall. I have never heard it in person.
Casey

Sorry to be jumping in here on this thread so late.

In my experience, low current wires such as cable or telephone connections don't hum - at least not from electricity. I'd be very surprised if that's what is really causing a hum.

If it were caused by wind, I'd expect it to vary with the wind conditions. You certainly wouldn't hear it all the time.

Here are a couple of things to try.

First, if you don't already know, you should learn what 60 Hz hum sounds like. Listen at the link below. If your house isn't making a steady hum at this pitch or with a strong component at this pitch, it's probably not electrical in nature.

If it does sound like this, you should look into it pronto. It could be something like a forgotten ventilation fan just above or below where you're listening. Or it could be a hum in an electrical panel, which may indicate a questionable circuit breaker or (worse) a loose connection. Sometimes such noises can be transmitted from locations surprisingly far removed from where you think you hear the noise.

Though it's not very likely, it could be something electrical inside the wall. The electrical code says that all connections and devices are supposed to remain accessable, but I've seen open boxes with live wiring and even live receptacles covered over with paneling, tile, and drywall in remuddled houses.

I'd suggest shutting off all the circuit breakers (or removing all the fuses) in your electrical panel. Then listen again. If you're still hearing the hum, open the main breaker or switch. If it's still there, and you're pretty sure it's an electrical sound, get an electrician to check it out.

If the hum goes away with all the breakers off, turn them on one by one until you find the one which makes the noise start up. That may help you to determine what circuits and devices the breaker/fuse supplies, and which of them might be making noise.

Here is a link that might be useful: 60 Hertz hum

I'm an electrical contractor, and I just left a house where there was a complaint of an intermittent buzzing noise. I went up in the attic to hear it strong but on the external at the house I went up on the roof and found that every now and then the phone line drop coming from the pole was vibrating on the metal bracket holding the insulator knob that it was connected to you could also feel the vibration at the telephone pole, and this telephone pole had no electrical on it only cable telephone so it's definitely possible. This is the first time I've ever seen anything like that happen on a phone line but there's no question that that is where it's coming from at least at this particular house. Sorry for the poor Grammer and type-os, using voice typing, but I wanted to post it here for future reference.