Few people can hear beyond 20kHz. Most adults can't even get that far.
Audio at 54 Khz by Tannoy
I was arguing with one of my friend today about the Tannoy super Tweeter witch can go up to 100Khz of frequency at -18 dB. But my friend was saying that this tweeter is for dumb people because the humain ear cannot go over the 20Khz frequency. I didnt agree with him but he really took out a good question. Any opinion?