3 ms·
Ultrasonic has a wavelength of 100 m - 1 km. Even if there were multiple sources, the peak area should be large. Also, neat frequencies are only made from mix
by willis936 6y ago
Ultrasonic has a wavelength of 100 m - 1 km. Even if there were multiple sources, the peak area should be large.
Also, neat frequencies are only made from mixing: a nonlinear operation. Most natural nonlinearities come from exciting resonant modes in objects in the path that absorb/retransmit.
- guywhocodes 6y agoI think you are off about 3-4 order of magnitude. 30kHz is about 1cm in air.
- willis936 6y agoIn free space: lambda = c / f lambda = 3E8 [m/s] / 10E3 [1/s] = 3E5 [m] You’d be right for acoustic waves, but we’re not talking about those.
- dariosalvi78 6y agoMaybe it was at hearing frequencies, but then it would have made electronic circuits emit sounds. I just can't figure this out in any reasonable way. There was another theory about ultrasound sounds used as rats repellent which would have created lower frequency sounds due to distortion. I find that one more credible.
- willis936 6y agoAcoustic infrasound also seems like a good candidate. There are actual studies about its effect on humans. Not everyone is affected, but the symptoms of sensitive people are similar. It’s even been weaponized by the US DoD!