What is this high-pitched ultrasound??
April 30, 2021 4:49 PM   Subscribe

For the last couple weeks, there's been an intermittent, super-high frequency permeating the two basement bedrooms in my house. What on earth is causing it??

This noise is very high-pitched; so high that neither my husband nor I are really sure that we're "hearing" it, so much as feeling intense pressure on our eardrums. My husband also feels the sound in his face (like sinus pressure) and is getting headaches from it. It seems to come and go; it lasts for several minutes and then seems to subside to a level where we're not quite sure if it's there, or if it's a residual sensation. He feels/hears it more often than I do.

Things we have tried:
- unplugging a TV that was in one of the rooms
- turning off other appliances including a nearby bathroom fan
- turning off all the electricity (flipping the main switch) and waiting to see if it stops

It doesn't seem to be stopping when I kill the power. It's definitely rooms on one side of the house, and strongest in one particular basement room. There's a power line outside, but I don't hear anything coming from the power line (or notice anything unusual when I go outside and stand right under it). What could it possibly be?? It's driving us mad and we can't get any work done in our offices. Please don't tell me it's ghosts.
posted by daisystomper to Home & Garden (18 answers total) 1 user marked this as a favorite
So you turned off the main power to the house at the meter and it continued? Next thing I might try is turning off the main water shutoff in case it’s some weird water flow issue.
posted by primethyme at 5:28 PM on April 30 [1 favorite]

posted by googly at 6:02 PM on April 30

Tangent: there are apps that appear to measure ultrasonic sound (within phone microphone sensitivity, obvs), maybe give one of them a try? At the sound pressure levels you seem to be describing they should pick it up pretty much instantly (if they do in fact work; I have no real ultrasonic sources near me to test with).

...then at least you'd have a frequency range and cycle time to work with when trying to track things down further, without spending the larger dollars required to buy a specialized detector (which do also exist, btw).
posted by aramaic at 6:11 PM on April 30 [1 favorite]

There must be sound meters that measure higher frequencies, and I think they're not crazy expensive. If you can measure it, maybe you can track it down. Looks like there are phone apps, not sure how accurate.
posted by theora55 at 6:13 PM on April 30 [1 favorite]

/high-5's atamaic
posted by theora55 at 6:13 PM on April 30

Do you by chance have a carbon monoxide detector in either of those rooms? A very similar thing happened to me, and it turns out it was CO detector code for needing new batteries.
posted by nautical twilight at 6:27 PM on April 30 [8 favorites]

Does everyone hear it consistently the same, as far as anyone can tell? I can understand if nobody is hearing it start or end, people just find themselves hearing it sometimes.

When you hear it, is all else quiet? And does it seem like these basement bedrooms absorb sound really well? It could be the kind of audio hallucination most people get when in sound-absorbing spaces that don't have other sound going on. I think this is less likely than an actual sound in this case. This form of hallucination is harmless and not indicative of psychosis or brain damage; it's just the effect of a rare situation the human brain was not built to comprehend correctly, e.g. a completely silent place.

I think it's more likely an actual sound, but I just wanted to throw this out there.
posted by Sunburnt at 6:27 PM on April 30 [1 favorite]

Got any fluorescent or compact fluorescent lights? Some of those start to sing just before they blow.

Similarly, the starter electronics of some streetlamps whine way up high when they're on the way out.
posted by scruss at 6:28 PM on April 30 [4 favorites]

You mentioned killing all the power didn't stop the noise. I'm wondering if there's something electronic with a battery back up (security system, uninterruptible power supply, battery powered smoke detectors, carbon monoxide detectors, bluetooth speakers, etc etc.) that might be causing it.
posted by Larry David Syndrome at 6:47 PM on April 30 [6 favorites]

Neighbors that might have put some noisemaking animal-deterrent device in the ground?
posted by ctmf at 7:05 PM on April 30 [17 favorites]

I'd double check that your carbon monoxide detectors are turned on.
posted by sebastienbailard at 7:58 PM on April 30 [3 favorites]

I bet ctmf is right.

There are bunches of 'ultrasonic', solar powered mole repellers out there, and a number use audible frequencies (one mentioned "400 Hz" which is way below ultrasonic, often specified as 20,000 Hz+).

The most advertised model looks like a long thick black tent stake with a square head.
posted by jamjam at 8:29 PM on April 30 [2 favorites]

I have a laptop charger that intermittently makes a very high pitched, faint noise. It was tough to localize and driving me crazy before I figured it out--not because of the noise itself, but because I couldn't figure out what was causing it.
posted by mark k at 11:31 PM on April 30 [1 favorite]

Know anyone with children? Get a young person help you locate the source of the noise. For what it’s worth, it could be a lightbulb.
posted by Namlit at 12:34 AM on May 1 [2 favorites]

Periodical cicadas?
posted by Thorzdad at 4:30 AM on May 1

It is cicada season, it wouldn't surprise me if they were making the noise.


Do you live near a park or other public grounds? Some cities/towns are using high pitched noise to discourage kids from congregating, apparently only youngins can hear it. I'm far from young and I can hear those damnable things, maybe you can too.
posted by james33 at 8:11 AM on May 1

Just given the time of year, an ultrasonic pest repellent stake installed by a neighbor would be my guess. Those things are super annoying, drive our dog insane even from across the street, and don’t even repel gophers/moles all that well. I can hear them, but most adults cannot. It could be a few houses away and still be having an effect.
posted by Wavelet at 2:38 PM on May 1 [1 favorite]

Tangent: there are apps that appear to measure ultrasonic sound (within phone microphone sensitivity, obvs),-- aramaic

I can verify that. There was a sound that was really bothering my son. So I pulled up a sound app (no longer in Google's store--but others should work). It picked up the 20+kHz tone that showed up every few seconds. Turned out to be something installed to scare mice/rats away. I was impressed with my son's hearing range!
posted by eye of newt at 9:31 PM on May 2 [1 favorite]

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