Please help me solve an acoustic mystery

Factual Questions
1

Starting two days ago, a high-frequency squeal began sounding non-stop in my bedroom. It’s hard to describe the volume level, so I hope it will suffice to say that it’s annoyingly loud. I’ve been forced to wear ear-plugs to drop the noise level enough to try to sleep or even spend any time there while awake.

If you go outside the room and close the door, the sound is vastly reduced. But once you open the door, it’s everywhere. And I mean that literally: after spending quite some time searching for the source and failing, I’m left with the conclusion that it does not come from any single identifiable source. The loudness is the same everywhere you go inside the room!

The character of the sound is most similar to high-pitched electrical motor squealing, somewhat akin to an automobile alternator on a older fan-belted engine. It’s closer to that than to electronic noise, like old TV’s used to make when operating out of spec.

After turning off things to see if the noise went away and it never did, I turned off the furnace and its fan and all electrical/electronic devices everywhere, but there was no change. I pulled the plug or battery on everything, too, such as my smoke and CO detector, also without change. So I decided to cut to the chase and I turned off all the circuit breakers for that room. Flashlight in hand, I returned to the room to find it was still making the same sound at the same volume!

Now, I well understand that many if not all of you will suspect that I’m imagining the sound or have some hearing problem. That’s what I’d think if someone reported the same thing I just have. All I can say in my defense that this is a real sound is that I only hear it in my bedroom and, more concretely, it shows up on my old Radio Shack dB meter. But the meter doesn’t indicate any significant change when I point it in different directions or move closer to any spot in the room.

There’s nothing above me but an attic, but the attic covers the whole area of that floor and I don’t hear it anywhere else. There are no fans or any devices whatsoever in the attic, and the sound is far too constant and unchanging to be coming from any biological source. There are no street lights nearby, and the sound is exactly the same 24 hours a day.

I’m a skeptic and so I don’t believe in ghosts or visiting extraterrestrials or any other New Age bullshit. But I have no idea what’s going on.

Any suggestions?
(p.s.: It is frequently difficult to get back here very often, for which I apologize. Please take that into account if it takes a while for me to follow up on this thread)

2

Well, I suppose the next step would be to physically remove each electrical item from the room, one at a time. That may help narrow down the problem.

3

I had a similar issue. It was my cable box.

4

What’s under the room?

5

I vote for gremlins.

6

what type of heating system do you have? air trapped in hydronic systems or steam systems can make noises at the start of heating season and need some maintenance.

7

What’s above the room? An roof fans up in the attic?

Another thing, if you’re up to it, turn off ALL your circuit breakers, then you can turn them back on one at a time and listen for the sound. Might be something as distant as a fridge compressor that is going up through the walls.
Is there any pipes near your room, Gas/Water/Freon?

8

My first though is that it is something electrical Turn off the main breaker for the house and see if it goes away. If it is something up in the attic or in the floor below then it’s entirely possible it is fed from a different circuit that still had power when you shut off the breaker for that room. If you kill the main breaker you are guaranteed to shut it off no matter what circuit it’s on.

My second thought is that it’s something like a well pump or some other type of underground pump. Depending on the construction of your building, the vibration cold be transmitted up through the walls so that it sounds like it is coming from your room when really it isn’t.

9

I’d try shutting off the main breaker first to rule out electrical. Then I’d shut off the water main to see if it’s water running through a pipe somewhere.
I’d also see if it was something vibrating in the room by pressing on various objects, windows, light fixtures, doors, etc.
Have you tried opening a window in the dead of night and listening for an exterior source?
Maybe a battery operated device that is running low on batteries?

10

Placing your ear directly on the house piping (or even on a faucet - something physically connected to the piping) will help in determining if the sound is water related or not. For that matter, if the OP puts his ear against the walls/floor/ceiling/windows in the room he may get a better idea of which direction the sound is coming from.

11

Look around around really carefully for a tea-pot that may be running on a propane stove. It may be in a closet or even under the bed, you never know. It is a long-shot but that is how I fixed the same problem once. The tea was pretty good though.

12

By any chance, does the Radio Shack meter you have tell you the frequency of the source? That might help narrow things down. Alternately (but equivalently), can you determine what musical note the sound is (such as by comparing it to an appropriate instrument)?

13

My first thought was that you had a nemisis plant one of these:

http://www.thinkgeek.com/gadgets/electronic/b278/

14

My guess is a toilet that’s barely running. The toilet in our master bath works itself to where it won’t quite turn off before water overtops the overflow tube.

ETA: Reminds me, I need to go adjust ours again.
ETA[sup]2[/sup] The last time I had a sound at night, it was our ceiling fan, but I’m guessing you would have thought of that.

15

Do you have kids? I had the same problem in my living room one night. It seemed to be coming from everywhere. It took an hour and a half of unplugging things and putting things to my ear to find the culprit. She had a toy that had batteries to make a noise of some sort and it had apparently broken and started making a quiet but headache inducing high pitched squeal. I didn’t even know it had batteries to make any sound before it went crazy.

16

My laptop makes a squeal when it’s running off of its battery rather than the current from the wall.

edit: and so wouldn’t be affected by the breaker

17

Power off, water off, water taps open and toilet flushed to relieve pressure on pipes.

If it’s a high pitch noise then it should be easier to locate because it is more directional in wavelength. If it affects your entire room fairly evenly then the sound is focused on it from another point. You could have a roof turret vent that needs oiling. These things will resonate like a tuning fork if the bearing is dry. TV antennas can resonate in the wind, water can resonate in pipes and anything that moves can squeak.
The power lines coming into my house are held up be a wire that is attached to a pivot. I have to grease that pivot regularly or it starts squeaking horribly.

18

Interesting. Alas, I have no cable or satellite box or the equivalent in my bedroom.

19

The main floor. My house has two floors.

When I go to the main floor, the sound cannot be heard, even from the ceiling of the main floor. In fact, if I walk away from my bedroom with the door closed, the sound disappears quickly.

As for whatever might be in-between the floors, I just tried putting my left ear against the floor of my room. The sound is the weakest there, while it is loud as ever in my right ear (facing the ceiling).

20

I’m afraid I don’t know what a hydronic heating system is.

I have a natural gas furnace in the basement, with the usual electric fan air distribution system using ducts. It’s about 30 years old.

I suspected it might be the source, so as I wrote in my OP: “I turned off the furnace and its fan and all electrical/electronic devices everywhere, but there was no change.”

Do you think it might be more subtle than that? Is there more info I might provide to assist?