Ringtone Adults Can't Hear

Is BS. I mean, the theory is correct. Adults starting at around the age of 25, start loosing their hearing. And that starts at the high end of the frequency spectrum. So technically, yes, there is a tone that a 40 year old teacher can't hear. What's BS is thinking your cellphone speakers can produce that tone. They can't. Anyone who has done some form of sound design knows this. How do you make someone sound like they are on a telephone? Cut out all the highs and all the lows. Because telephones can't reproduce those tones. Now your ringtone might produce a tone, and it might be at a low volume, and your teacher might not hear it, but that doesn't mean they are incapable of hearing it! :)