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
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.
That's what I thought... Also, where is the 90 kHz carrier supposed to come from
http://scent-itn.org/emi_cenelec_freq.htmlI 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.pdfIf you need to visit a lovely place, Brittany is nice, and want to experiment the trouble by yourself, my home is open
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.
the bakery's ovens
I would say the bakery still remains a possibility, but also a noise, or even a B Factor on a A+B problem.