From public anemone Sent Wed, Feb 17th 1999, 15:27
Che wrote: > >i am not versed in the science of sound, but can > >humans hear over 20 khz? > > I can. Ultrasonic sensors drive me nuts. me too...but neither you nor i can actually hear them...what we do hear is the effect of the ultrasonic sensors heterodyning the air and creating harmonics below the actual tone...i.e. a 30khz tone might give off some low volume 15khz harmonics, which you can hear if you have good ears...to see if you can actually hear 20+ k tones, you really need to listen to them on good headphones in one of those listening test type environments...(i.e. you can't see when someone is or isn't playing a tone)