Yeah I can hear it, its not that annoying either. Some people say that cant stand it. Its not pleasant... but its not something that I would scream and run away from.
If you are over 20 something you will not be able to hear it, this is due the the frequency and hearing decay in age, you lose high frequency tones first.
Well, the dog didn't seem to care. I heard it though, my ears kinda hurt now since I played it at full volume for the last few minutes trying to hear it. Once I did . . . ouch!