This sound frequency peaks just at 15Khz and there is a very slight harmonic at 9KHz, 3KHz. You need to have a pretty heavy internal ear damage to not hear this one if you aint too old. My father is limited to 14Khz (He is 65) and can't hear the crickets at night and some birds.
And of course... while I was typing, some guy posts a nice little link with a whole bunch of sounds with frequency labeling
