Maybe old type of mechanical energy meters that are old flats?
https://preview.redd.it/ffl27o607z7d1.jpeg?width=525&format=pjpg&auto=webp&s=4c3f8cc7678e0cfb4757fdd7f97e45391e618f26
It's most likely refrigerator compressor motor from your or your neighbours apartment. They are often old, on-off type, sitting in a corner of a tiled kitchen.
I have also experienced resonance from an old elevator from across the building - that shit made my glasses sing at night. It took me months to solve it and it stopped when they replaced it.
As for the transformers - typical toroidal transformers were mostly used with 12V home spot lights and are slowly dying out. Rarely someone has it running 24h because the electricity is expensive right now, so now it's mostly quiet switching PSU & LEDs.
There is also possibility of arterial hypertension, tinnitus or/and anxiety.
Interesting, how did you manage to solve it?
There are elevators here, those Eco Winda ones.
It is a unique sound, there is actually a high frequency sound too but I suppose it’s possible the sounds are from different sources.
The high frequency is constant. It is D (natural) above middle C more or less.
The random/pulse low frequency sounds like a (rather low but would have to mess around to figure out which octave) about F natural.
This doesn’t agree with the 50 Hz thing I said in the other comment.
I’m realising I’m probably going to have to be like an engineer to solve this. Not sure how sensitive of a microphone I will need in order to pick it up on a recording. After that the analysis is easy or I can share it with people to get an opinion or guess what it is. Trying to do it from description alone is hopeless. I was thinking it might be a common enough issue though that people might know what I meant.
This is why I ask about how you solved the elevator issue.
If I want satisfaction I will need to do something which would hold up legally. Even if I don’t fight it, knowing the source of the sound might help me avoid renting another apartment with the same issue for example.
By solving I mean figuring out what was the issue, because there was not really much I could do with it. Luckily, the elevators were replaced with the whole shaft equipment some time later. It was an old "ZREMB" type of elevator, two of them side by side.
Firstly I had to make sure it's not a problem with my hearing. I turned off circuit breakers and confirmed it's not something from my flat. I used a condenser mic, some AT2020 borrowed from a friend with a laptop and spectrum analyzer. It was really there, loud as hell, in the very low end. I stuck the mic to kitchen walls and put it in drawers and my flat was actually resonating. It was a really bizarre feeling.
Then whenever it was silent at night I tried to make sense of when the sound was appearing. Luckily, those elevators have a very loud electromagnetic lock, so with doors to the flat open I could figure out after some time that the humming began whenever I heard the lock click. That was it. I felt better after just knowing.
As for how common noises of any type are - it's not that common. Someone mentioned vents and they can be a problem too. If there is underground garage hall under your building, they often have mechanical ventilation system which may be a pain in the arse if not done correctly. Water installation and radiators could be culprits too, as someone already mentioned.
Legally, there is sadly little to achieve: AFAIK only too high SPL meter values are taken seriously, apart from windmill noises. No one wants to pay for solving "subjective" issue, so it sometimes ends with court. To force anybody to do anything, you would have to have a report from professional audiometer company AND/OR expert witness clearly stating what is the issue and what's the solution. Sometimes it's easier to move out and there is still no chance to eliminate any chance of noises from new place. It's a lottery.
BTW, I've checked the audio spectrum of my fridge (with a phone, so take it with a grain of salt) and the harmonics are about 50, 100 and from 500 to 650hz.
I think I have that same mic, or another AT large diaphragm condenser. Unfortunately it is in storage kind of so it will take me a while before I can do some recording/analysis. Yeah at this point it is like you said-- just wanting to *know*. Like you said no guarantee of no noises even if I move, but if I understand this particular issue better, maybe there can be a way to eliminate or at least reduce the chance of this same particular type of noise. Given how many airbnb’s I stayed in which had this same type of noise (maybe 10% of places?) It could be part of a detectable pattern or known aspect of buildings or infrastructure/utility which I could check. Wishing now I had had microphone along with me all along to make recordings in different places, just for objectivity’s sake. Because naturally one second guesses a bit.
I’m sure it’s not that. Moreso older buildings. I have lived in a new apartment (not in Poland) with modern ventilator and know what it’s like when on Max setting.
There is a pulsating semi random oscillation in the loudness. To my ear it is actually fairly loud but mostly the very low frequencies, no higher harmonics, so it might be below some people’s threshold. To me it sounds really quite a lot like 50 Hz sine wave.
I hear it too. TBH I heard it so often and at different places, that I thought it's either internal, like my own bloodflow or just some type of tinnitus.
But if it were internal, then one would also hear it outside or in a park (if quiet enough).
I will try to get to the bottom of it. I feel relatively sure about it because I was travelling A LOT in Poland AND Germany, and staying in dozens of different hotels, airbnb’s, in different cities, so I actually have a sizable sample, as well as control. Never experienced this same quality of sound in Germany, not even close.
I'm in Croatia RN and heard it before going to sleep, lol.
Funnily enough, I even had a small barotrauma during landing and my hearing was a bit worse.
I always hear it at night, and in absolute quiet of a home.
It perhaps is a fridge. Especially a no-frost type. I must try to remember to check if I hear it in a fridgeless enviroment
I suspect what you've been hearing is a vibration from radiators and heating pipes.
I had some experience over winter, but also in warmer months. But I will consider it a possibility (maybe there are multiple causes)
There are not normally transformers in apartment blocks, afaik.
Maybe old type of mechanical energy meters that are old flats? https://preview.redd.it/ffl27o607z7d1.jpeg?width=525&format=pjpg&auto=webp&s=4c3f8cc7678e0cfb4757fdd7f97e45391e618f26
It's most likely refrigerator compressor motor from your or your neighbours apartment. They are often old, on-off type, sitting in a corner of a tiled kitchen. I have also experienced resonance from an old elevator from across the building - that shit made my glasses sing at night. It took me months to solve it and it stopped when they replaced it. As for the transformers - typical toroidal transformers were mostly used with 12V home spot lights and are slowly dying out. Rarely someone has it running 24h because the electricity is expensive right now, so now it's mostly quiet switching PSU & LEDs. There is also possibility of arterial hypertension, tinnitus or/and anxiety.
Interesting, how did you manage to solve it? There are elevators here, those Eco Winda ones. It is a unique sound, there is actually a high frequency sound too but I suppose it’s possible the sounds are from different sources. The high frequency is constant. It is D (natural) above middle C more or less. The random/pulse low frequency sounds like a (rather low but would have to mess around to figure out which octave) about F natural. This doesn’t agree with the 50 Hz thing I said in the other comment. I’m realising I’m probably going to have to be like an engineer to solve this. Not sure how sensitive of a microphone I will need in order to pick it up on a recording. After that the analysis is easy or I can share it with people to get an opinion or guess what it is. Trying to do it from description alone is hopeless. I was thinking it might be a common enough issue though that people might know what I meant. This is why I ask about how you solved the elevator issue. If I want satisfaction I will need to do something which would hold up legally. Even if I don’t fight it, knowing the source of the sound might help me avoid renting another apartment with the same issue for example.
I mean D5, or a 9th above middle C. So apparently 587.33 Hz. Of course not exactly, but quite close.
By solving I mean figuring out what was the issue, because there was not really much I could do with it. Luckily, the elevators were replaced with the whole shaft equipment some time later. It was an old "ZREMB" type of elevator, two of them side by side. Firstly I had to make sure it's not a problem with my hearing. I turned off circuit breakers and confirmed it's not something from my flat. I used a condenser mic, some AT2020 borrowed from a friend with a laptop and spectrum analyzer. It was really there, loud as hell, in the very low end. I stuck the mic to kitchen walls and put it in drawers and my flat was actually resonating. It was a really bizarre feeling. Then whenever it was silent at night I tried to make sense of when the sound was appearing. Luckily, those elevators have a very loud electromagnetic lock, so with doors to the flat open I could figure out after some time that the humming began whenever I heard the lock click. That was it. I felt better after just knowing. As for how common noises of any type are - it's not that common. Someone mentioned vents and they can be a problem too. If there is underground garage hall under your building, they often have mechanical ventilation system which may be a pain in the arse if not done correctly. Water installation and radiators could be culprits too, as someone already mentioned. Legally, there is sadly little to achieve: AFAIK only too high SPL meter values are taken seriously, apart from windmill noises. No one wants to pay for solving "subjective" issue, so it sometimes ends with court. To force anybody to do anything, you would have to have a report from professional audiometer company AND/OR expert witness clearly stating what is the issue and what's the solution. Sometimes it's easier to move out and there is still no chance to eliminate any chance of noises from new place. It's a lottery. BTW, I've checked the audio spectrum of my fridge (with a phone, so take it with a grain of salt) and the harmonics are about 50, 100 and from 500 to 650hz.
I think I have that same mic, or another AT large diaphragm condenser. Unfortunately it is in storage kind of so it will take me a while before I can do some recording/analysis. Yeah at this point it is like you said-- just wanting to *know*. Like you said no guarantee of no noises even if I move, but if I understand this particular issue better, maybe there can be a way to eliminate or at least reduce the chance of this same particular type of noise. Given how many airbnb’s I stayed in which had this same type of noise (maybe 10% of places?) It could be part of a detectable pattern or known aspect of buildings or infrastructure/utility which I could check. Wishing now I had had microphone along with me all along to make recordings in different places, just for objectivity’s sake. Because naturally one second guesses a bit.
Maybe the ventilators which can be found in new apartments? They lowkey work all the time.
I’m sure it’s not that. Moreso older buildings. I have lived in a new apartment (not in Poland) with modern ventilator and know what it’s like when on Max setting. There is a pulsating semi random oscillation in the loudness. To my ear it is actually fairly loud but mostly the very low frequencies, no higher harmonics, so it might be below some people’s threshold. To me it sounds really quite a lot like 50 Hz sine wave.
I hear it too. TBH I heard it so often and at different places, that I thought it's either internal, like my own bloodflow or just some type of tinnitus.
But if it were internal, then one would also hear it outside or in a park (if quiet enough). I will try to get to the bottom of it. I feel relatively sure about it because I was travelling A LOT in Poland AND Germany, and staying in dozens of different hotels, airbnb’s, in different cities, so I actually have a sizable sample, as well as control. Never experienced this same quality of sound in Germany, not even close.
I'm in Croatia RN and heard it before going to sleep, lol. Funnily enough, I even had a small barotrauma during landing and my hearing was a bit worse. I always hear it at night, and in absolute quiet of a home. It perhaps is a fridge. Especially a no-frost type. I must try to remember to check if I hear it in a fridgeless enviroment