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| Request for knowledge - Troubles at home |
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| nctnico:
--- Quote from: IanB on June 08, 2022, 01:57:41 pm --- --- Quote from: tom66 on June 08, 2022, 10:48:40 am ---Most big cities in hot parts of the world have air con for apartments and houses, and besides faulty units I've never thought they were all that loud while running. --- End quote --- That's not my experience. --- Quote from: pcprogrammer on June 08, 2022, 11:19:58 am ---Could not sleep due to the air-conditioning units on the roof. There was no quit spot in the room to be found. --- End quote --- This. In hotel rooms that have one of those window mounted or wall mounted aircon units, they are usually so noisy that I cannot sleep with them running. I have a choice of a cool room with too much noise, or a quiet room that is too hot. My usual strategy is to run the thing at max all evening, then turn it off before sleeping. --- End quote --- Same here. I have fights with my wife over having the aircon on in hotels because they make too much noise for me to sleep well. Things get worse if the hotel room is in a bad position where you can hear the outside units. Definitely a reason to change to a different room. At home I installed the quietest aircon I could find and mounted it the indoor unit in the hallway instead of in the bedroom. |
| lxmute:
Hello, Your replies were helpful to bring me back to the "sound aspect" problem. Requesting help from a specialist in EMI and its derivatives, I've been led to the problem of Infrasounds generated by harmonics inducted by high power + high frequencies (moderated since in 90kHz range) at a low frequency range on unshielded city grid cables. Sacrebleu! I think I'm in a deep sh?t to monitor this with accuracy. |
| EEVblog:
--- Quote from: lxmute on July 02, 2022, 07:31:07 am ---Hello, Your replies where helpful to bring me back to the "sound aspect" problem. Requesting help from a specialist in EMI and its derivatives, I've been led to the problem of Infrasounds generated by harmonics inducted by high power + high frequencies (moderated since in 90kHz range) at a low frequency range on unshielded city grid cables. --- End quote --- Err, how do the city power cable induce low frequency sound? What is the physical mechanism? Sorry to tell you, but it sounds like you have been peddled some BS :bullshit: |
| ebastler:
That's what I thought... Also, where is the 90 kHz carrier supposed to come from, with a 50 Hz power grid and mainly resistive loads in the bakery's ovens? Sounds like that "specialist in EMI" might be someone who cashes in on people's diffuse fears of "bad electrical fields" by selling them some phantasy consulting services. Does he have a name and a website maybe? |
| lxmute:
--- Quote from: EEVblog on July 02, 2022, 09:19:55 am ---Err, how do the city power cable induce low frequency sound? What is the physical mechanism? Sorry to tell you, but it sounds like you have been peddled some BS :bullshit: --- End quote --- My query came from 2 assertions made on an industrial keynote about shielding, « the higher the power, the bigger this EMI becomes » « high voltage in addition to high frequency, you generate low frequencies EMI » The doctor speaking was talking about high frequencies in general, producing some harmonics going into lower frequencies. So I simply requested, if it can be possible, that on a high power source, a lower frequency that what you expect when saying high frequencies, some RF signal then, could also produce some harmonics, in a lower range, so very low range frequencies, so infrasounds, was a domain of possibilities. I received a firm confirmation. 90kHz is what I call "RF" here, since it's in the RF range field. Correct me if I'm wrong. --- Quote ---That's what I thought... Also, where is the 90 kHz carrier supposed to come from --- End quote --- http://scent-itn.org/emi_cenelec_freq.html I will put efforts into improving my RaspiBoom noise cancellation. I also would like to put my hands on such device: http://article.nadiapub.com/IJSIP/vol8_no9/22.pdf If you need to visit a lovely place, Brittany is nice, and want to experiment the trouble by yourself, my home is open ;D A last note, there is a bloom in France of people being hardly hit by infrasounds, on the whole territory. Which ignited 2 years ago my curiosity. and btw I'd just like to get back to normal things in my life. Coding, Woodworking, Sailing. Just a few months of stamina, I sold out my business and just quit the frogs country. :-+ --- Quote ---the bakery's ovens --- End quote --- I would say the bakery still remains a possibility, but also a noise, or even a B Factor on a A+B problem. |
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