I could only hear up to 12Khz but I'm on an office PC with built in speaker and it's not very loud to begin with. I'll have to try at home, I'll probably be able to hear them all. I can hear lot of frequencies people can't, like TVs, light bulbs, etc. when you get into the 15khz zone your hardware can be a limitation too, the speakers may not produce it at all, or even properly.