120 hz hum-- not from my audio gear but from my house-- what to do about it?

[computer-audiophile]

Excerpt from a German website:

"Not all people hear equally well
Often, those affected doubt themselves. They hear a buzzing sound, but other family members do not notice it. In fact, some people hear better than average, especially the very soft sounds. This apparent advantage quickly turns into the opposite when the noise is perceived as disturbing or even "annoying".

When microphones reach their limits
Microphones offered cheaply for private users usually only measure sounds with a sound level of 30 dB and higher. Applications for smartphones are subject to a similar limitation. To measure and classify very quiet sounds, the user needs high-quality equipment for sound measurement.

Measuring with the low-noise microphone
measure low sound levelsThe special microphone from the PCB Piezotronics company in the USA was designed for recording very quiet sounds. With a low self-noise of 4.6 dB, it is more than 10 decibels lower than a good Class 1 microphone. The low-noise microphone is therefore well suited for hum detection in conjunction with the XL2 sound level meter and frequency analysis."

 

[egellings]

Yes indeed, it's tough to get away from line induced pickup. Well-shielded steel boxes have worked for me, when designing sensitive circuitry. But it's probably no fun living in a steel box!

My workplace had a screen room, a small copper clad room used when measuring electronics requiring complete isolation from RFI. Electrical power outlets in the room had special filtering to prevent them from carrying RFI into the room. Ventilation duct was also designed in a way to stop RFI ingress. We manufactured electronic modules and some of them required use of the room in their testing. We had one employee, a test system operator who claimed that the tester was making her sick due to some sort of radiation. The testers were just racks of low power voltage & signal sources and various metering equipment, and they could not have radiated anything that could sicken someone. The company had a hand-held RFI meter, and I explained to her that it could measure and show any radiation. Running it near the tester showed just background noise. I asked the operator to come into the screen room and see if she got any relief from the discomfort in there. I explained to her that the copper cladding kept RFI out of the room. She claimed immediate relief! Unbeknownst to her, I had set up an RF generator that generated random RF noise into a small antenna, and when I turned the RFI meter on in that room and showed her the reading, the meter showed a large reading. I then told her that she was lying about discomfort at the tester, because the room had enough RF in there to nearly fry an egg! We went back to the tester, where the meter showed just a bit of background noise. She quit complaining after that. I said that if RFI were strong enough to cause discomfort, surely other employees would have noticed & complained about it. No one else did. The company let her go a couple of months later. She just complained too much about anything and everything affecting her health in some way or another.

 

[DVDdoug]

I have had this problem in every house and apartment I've ever lived in. I

That's weird... I assume you are in the U.S (where 120Hz is a harmonic of 60Hz)? If you are hearing 120Hz in Europe it's not power-line related...

We do tend to hear the harmonics because our ears are less sensitive, the lower the frequency.

Humming/buzzing is very common from transformers. I rarely hear anything from transformers mounted on power poles but it's common from transformers mounted on the ground (or in basements or utility rooms, etc.). And that could get transmitted through the building's foundation.

If I listen carefully, I can hear my refrigerator buzzing/humming form my living room. But I'm used to it and not really aware of it.

 

[sarumbear]

You are just one of the many who hears the hum. All over the world. There are parts of structures where the resonance is the greatest, some walls, rooms or in my case a few places where it is quite loud under the house (it's a pole home).

Cracking the mystery of the ‘Worldwide Hum’

Shortly after Glen MacPherson started hearing strange humming noises, he created the World Hum and Database Project so people around the world could document their own experiences with the Hum.

theconversation.com

I proved a long time ago it is unrelated to the electrical connection to my home.

Has anyone show that on FFT analysis?

 

[computer-audiophile]

My workplace had a screen room, a small copper clad room used when measuring electronics requiring complete isolation from RFI.

When I worked at the Physics Institute at Heidelberg University, we had a shielded measuring bunker deep underground for sensitive experiments. But for extremely sensitive radiation measurements with Geiger Müller counting tubes, we had to come up with tricks to differentiate the particles from cosmic radiation that penetrate the earth.

 

[egellings]

When I worked at the Physics Institute at Heidelberg University, we had a measuring bunker deep underground for sensitive experiments. But for extremely sensitive radiation measurements with Geiger Müller counting tubes, we had to come up with tricks to differentiate the particles from cosmic radiation that penetrate the earth.

I worked only with electrical radiation, not with other types of it.

 

[Soandso]

Bellow cited journal posits that "hum" (30 - 80 Hz) is a an interaction between the receptors of cochlear hair cells and those of the semi-circular canal. I will summarize without specifying what are any direct quotations of the author Franz Gunther Frosch.

The semi-circular hair cells exhibit self-sustained oscillation, which involves longitudinal moving sound pressure waves perceived in the cochlea. This interaction takes place at less than 1/2 the cycle of the oscillating hum (ex: 7 milli-seconds for 70 Hz "hum"). The "hum" volume arises in the cochlea, while the "hum" oscillations arise in the semi-circular canal.

Quick head rotation horizontally raises pressure in the semi-circular canal altering those hair cells oscillation pattern and thereby suppressing the "hum". A common corollary is how the "hum" disappears for 2-3 days after long distance air travel, since pressure rose in the ear.

Citation: "Possible joint involvement of the cochlea and semi-circular canals in perception of low-frequency tinnitus, also called "The Hum" or "Taos Hum"; free full text available on line from the International Tinnitus Journal"

 

[sarumbear]

Bellow cited journal posits that "hum" (30 - 80 Hz) is a an interaction between the receptors of cochlear hair cells and those of the semi-circular canal.

That’s how we hear anything isn’t it?

Citation: "Possible joint involvement of the cochlea and semi-circular canals in perception of low-frequency tinnitus, also called "The Hum" or "Taos Hum"; free full text available on line from the International Tinnitus Journal"

In short it’s a type of tinnitus.

 

[Andolink]

I assume you are in the U.S (where 120Hz is a harmonic of 60Hz)?

Yes, I'm in the southwestern U.S. I do believe this to be a hum originating from the electical circuitry of the house precisely because 120 hz is a harmonic (i.e. one octave above) the standard 60 hz generated by all electrical circuits.

 

[fpitas]

Unfortunately, even if it doesn't go away when you disconnect the house breakers, that may not be conclusive. The earth is used as a reference for the power grid. Generally there are wires strung to minimize ground currents, but that isn't perfect. Definitely worth making sure it's not from your house, though, in case there is a fixable problem.

 

[robwpdx]

Yes, I'm in the southwestern U.S. I do believe this to be a hum originating from the electical circuitry of the house precisely because 120 hz is a harmonic (i.e. one octave above) the standard 60 hz generated by all electrical circuits.

Without putting a spectrum analyzer-FFT on your power line with appropriate protection from line currents - analyzer software for your computer as many ASR commenters do, you might ask your power company about "power quality" which includes measurement of harmonics. Inverters create harmonics by their nature. A power quality analyzer, including harmonics, is an instrument rental item, and a local university may have one. It sounds frustrating, hope it works out.

 

[robwpdx]

My workplace had a screen room, a small copper clad room used when measuring electronics requiring complete isolation from RFI. Electrical power outlets in the room had special filtering to prevent them from carrying RFI into the room. Ventilation duct was also designed in a way to stop RFI ingress. We manufactured electronic modules and some of them required use of the room in their testing. We had one employee, a test system operator who claimed that the tester was making her sick due to some sort of radiation. The testers were just racks of low power voltage & signal sources and various metering equipment, and they could not have radiated anything that could sicken someone. The company had a hand-held RFI meter, and I explained to her that it could measure and show any radiation. Running it near the tester showed just background noise. I asked the operator to come into the screen room and see if she got any relief from the discomfort in there. I explained to her that the copper cladding kept RFI out of the room. She claimed immediate relief! Unbeknownst to her, I had set up an RF generator that generated random RF noise into a small antenna, and when I turned the RFI meter on in that room and showed her the reading, the meter showed a large reading. I then told her that she was lying about discomfort at the tester, because the room had enough RF in there to nearly fry an egg! We went back to the tester, where the meter showed just a bit of background noise. She quit complaining after that. I said that if RFI were strong enough to cause discomfort, surely other employees would have noticed & complained about it. No one else did. The company let her go a couple of months later.

Thanks for your experience. I have worked in wireless and studied EMF and biology. I don't want to do it on this thread, but the theory (and measurements) of EMF on the body/biological systems, and a different one on the theory of EMF interference into the audio band would be good master topics.

 

[computer-audiophile]

I have had this problem in every house and apartment I've ever lived in.

It is precisely this statement that I find strange. Of course, one would have to know more about these places.

 

[Speedskater]

Hard to schedule, but what about a neighborhood power outage.

At home I sometimes hear what sounds like a pump or compressor.

 

[Andolink]

It sounds frustrating

Indeed. To continuously have a "wrong" note added to every piece of music I Iisten to after all the efforts I've made over the years to achieve the best audio playback possible. Ugh!!

 

[sarumbear]

It is precisely this statement that I find strange. Of course, one would have to know more about these places.

Or more about his tinnitus.

 

[Andolink]

I'll report back here in a few days after conducting the main breaker switch off test. Thanks for all the helpful comments.

 

[Soandso]

Bellow cited journal posits that "hum" (30 - 80 Hz) is a an interaction between the receptors of cochlear hair cells and those of the semi-circular canal. I will summarize without specifying what are any direct quotations of the author Franz Gunther Frosch.

The semi-circular hair cells exhibit self-sustained oscillation, which involves longitudinal moving sound pressure waves perceived in the cochlea. This interaction takes place at less than 1/2 the cycle of the oscillating hum (ex: 7 milli-seconds for 70 Hz "hum"). The "hum" volume arises in the cochlea, while the "hum" oscillations arise in the semi-circular canal.

Quick head rotation horizontally raises pressure in the semi-circular canal altering those hair cells oscillation pattern and thereby suppressing the "hum". A common corollary is how the "hum" disappears for 2-3 days after long distance air travel, since pressure rose in the ear.

Citation: "Possible joint involvement of the cochlea and semi-circular canals in perception of low-frequency tinnitus, also called "The Hum" or "Taos Hum"; free full text available on line from the International Tinnitus Journal"

A later (2022) "hum" article by the same author in the same journal (full text available free on line) cited below is more technical. I will again summarize only some select points and, as previously, forgo specific quotation marks of the author's words for readability here.

Different external sound frequencies can have duration period variation; when 2 frequencies are synchronized these are in phase. Hum introduces a phase shift in 1 of the frequencies, whereby they are not in phase.

In the ear vestibule mechanical energy converts to electrical energy, and in the outer hair cells that electrical energy converts to mechanical energy. The hum phase shift happens when the mechanical to electrical to mechanical to electrical energization cycle continues in a coordinated loop because then normal oscillations' synchronization fails.

It is the phase shift of a sound frequency next to another frequency that both "tunes" (author's own word) the frequency of a hum and creates volume of that hum. The vestibular-cochlea interaction area is where hum interacts with sound.

I'll point out that the author specifies (in addition to the previously mentioned quick horizontal head movement and air travel) that jogging is reported to inactivate the hum. So the O.P. might want to experiment with some controlled jogging when next hears the hum to see if that has any effect. This cited research is basically deeming the hum as a subset of tinnitus.

Citation title: "A resonant circuit involving the vestibule and cochlea base could cause extremely low-frequency tinnitus, also called "The Hum" or "Taos Hum".

 

[Haflermichi]

You did not answer the question of if you've ever had your hearing checked or seen a hearing specialist.
This is a science based forum.
There are only two variables: "Every apartment and house you've ever lived in" and you.
If you really want and answer for yourself you have to be willing to include yourself as the possible problem source.
There are various forms of hearing and vestibular maladies.
You mentioned you only noticed this phenomenon indoors and don't notice it outdoors. Well, I've got news for you.
Outdoors is seldom quieter than a closed room in nearly any house.

 

[Andolink]

you have to be willing to include yourself as the possible problem source

The fact that there are both indoor and outdoor environments, (including caves, where the ambient noise level is nil) where I hear no hum makes it pretty certain that I'm not the source of the problem.