I was reading that some shop owners use this type of thing to keep teens from hanging out around their stores, they use the 18 and under ones, the adults cannot hear it, but it drives the kids nuts
BTW I am mid 30's and I cannot hear anything below the 30 one
lol does anyone notice when you play the ones that you cant hear, you flinch a bit , my eyebrows kinda twitch and my ears kinda feel weird..? This just me?
im 27, and the last one I can hear them everyone-down to 30...then i dont hear the rest...
but ive only got 1 working ear anyway...ive got that thing where a the tiny bone in my ear that is integral to the function somehow-has either become broken or siezed up-cant virate and so im 90% deaf in my right ear....
I'm 21, and the first one I hear is the 17.4khz 24 & younger. I kind of hear the one before that but only if I'm really listening for it. That shit gave me a headache. My Jack Russel tripped on the 60 younger one.
I can hear everyone including up to 17.4 K, which is good, because I'm not a kid.
And also, those last few ones (the very high ones) are pretty useless IMO, because I kind of doubt that many phone speakers can even play back that high of a frequency.