« on: 18/04/2015 20:49:09 »
"I'm not aware of any research which shows that ultrasound in air is influenced by magnetic fields"
This guy on a blog wrote-
" ........ However, the difference between no shielding and just one sheet with magnets is significant for me and very noticeable relief."
Your question was about magnets and ultrasound. My statement still stands.
Any dense material will reduce the level of sound transmission compared to free air. This seems to be the comparison here. Heavy magnets will increase the density of the sheet. Concrete and brick would work better with less chance of unwanted resonance.
You need to look carefully at how he is measuring the reduction, doesn't sound very scientific to me.
If you are troubled by HF sound, possibly just above your hearing range, then you are better looking for the source. HF range in free air is quite short, so the source is most likely to be inside the house. Look for CH pumps, fans, computer and TVs, even some phone chargers. Try switching off one at a time. Problem is some sources can be intermittent and switching off can interrupt the steady state, eg by cooling, and the sound goes away for a while, so switching off everything and then back on one at a time might not work.
I know some people are troubled by HF noise, but if you approach it scientifically you have a chance of finding it. If you look to pseudoscience, you have little hope!
What distance can ultrasound be projected through air? Would a bat detector pick up the sound and if so what would it sound like to human ears? Like the testing from emergency broadcast system alerts?