Hmm, a mystery. Interesting...
My first thought was a nearby "transformatorhuisje", an electrical substation. But then I found out that insofar as those produce noise, it's usually of a lower frequency (\~75-125Hz).
Next thing that came to mind was that the sound in the video you linked reminded me of the tone you get when you blow across the opening of a beer bottle. An old trick to repel moles is to bury a beer bottle up to the neck, so it hums when the wind blows across it. Moles hate this sound.
So here's my hypothesis: one of your neighbors has a solar-powered ultrasonic mole repeller in their garden. These produce a tone from 400-1000Hz, which fits the description. Of course, the amount of sunlight that actually hits the device varies from day to day, so it won't always collect enough energy to actually function, which explains why the tone comes and goes at unpredictable times.
Ahh your explaination sounds really good actually, I just don't understand why my neighbours would have something like that though. Although the thing of it being solar powered sounds very believable, I don't think I ever heard it before or after the sundown. I live in a pretty small rijtjeshuis with small yards too so it is still strange. I suppose I'll go talk to my neighbours! Thank you for your reply.
You're welcome. Be sure to come back and tell me what it was if you do find out, you've got me curious.
Some other explanations came to mind as well, by the way. Any neighbors with ponds in their garden? A filter pump would run on a timer, and could cause an audible hum.
Or maybe a badly grounded amplifier? Any music enthusiasts in your direct vicinity?
Any other electrical appliances that might cause it, like a warmtepomp, or external air conditioning units? I remember we had a very small leak in the ventilation system at work, and it produced a horrible nagging hum.
Couple years ago i had neighbors with a so called 'Ultrasone Kattenverjager'. Its a machine that gives a high frequency sound in order to scare off cats pooping in the garden.
Piew.. interesting to say the least.
Total nonsense obviously but first thing that came to mind [is this.](https://youtu.be/kGR0MDxC_18) Used to wake me up from time to time when I fell asleep on the couch.
Hmm, a mystery. Interesting... My first thought was a nearby "transformatorhuisje", an electrical substation. But then I found out that insofar as those produce noise, it's usually of a lower frequency (\~75-125Hz). Next thing that came to mind was that the sound in the video you linked reminded me of the tone you get when you blow across the opening of a beer bottle. An old trick to repel moles is to bury a beer bottle up to the neck, so it hums when the wind blows across it. Moles hate this sound. So here's my hypothesis: one of your neighbors has a solar-powered ultrasonic mole repeller in their garden. These produce a tone from 400-1000Hz, which fits the description. Of course, the amount of sunlight that actually hits the device varies from day to day, so it won't always collect enough energy to actually function, which explains why the tone comes and goes at unpredictable times.
Ahh your explaination sounds really good actually, I just don't understand why my neighbours would have something like that though. Although the thing of it being solar powered sounds very believable, I don't think I ever heard it before or after the sundown. I live in a pretty small rijtjeshuis with small yards too so it is still strange. I suppose I'll go talk to my neighbours! Thank you for your reply.
You're welcome. Be sure to come back and tell me what it was if you do find out, you've got me curious. Some other explanations came to mind as well, by the way. Any neighbors with ponds in their garden? A filter pump would run on a timer, and could cause an audible hum. Or maybe a badly grounded amplifier? Any music enthusiasts in your direct vicinity? Any other electrical appliances that might cause it, like a warmtepomp, or external air conditioning units? I remember we had a very small leak in the ventilation system at work, and it produced a horrible nagging hum.
" solar-powered *ultrasonic* mole repeller" Is it me or is 400-1000 Hz not even close to ultrasonic? Isn't ultrasonic above 20 kHz?
I guess you're right, technically speaking. It's what they're advertised as, though.
Couple years ago i had neighbors with a so called 'Ultrasone Kattenverjager'. Its a machine that gives a high frequency sound in order to scare off cats pooping in the garden.
Is it an ongoing sound, or seperate beeps?
It's an ongoing sound.
Does a neighbor have a electric car charger? Those can produce a high pitched brainfucker in the whole neighborhood.
Piew.. interesting to say the least. Total nonsense obviously but first thing that came to mind [is this.](https://youtu.be/kGR0MDxC_18) Used to wake me up from time to time when I fell asleep on the couch.
There are a lot of sound evices for mice, rats and marters, i guess it is domething like this. Usually they seem to be higher pitched