I recently tested the frequency range from 10Hz to 20kHz. I found I stop hearing clearly audible signal at 15kHz. I believe this is just my hearing, though (getting a bit older). I still sense aural pressure in the 16kHz-18kHz range. Anything above 18kHz and I do not hear/feel anything.
These speakers seem to perform well within the frequency range for average human hearing capability. If you can actually pick out lost 17kHz+ frequencies from within a sound field, you have very impressive hearing indeed.
Trust me those speakers do that and much more. They are great speakers and can put out whatever you desire. The speakers also seem to be made with kevlar in some parts, So these speakers are very capable of not breaking. However, the tweeters seem to become defective easily, but you can not tell it. Mine were defective in every speakers, couldn't tell a difference in having it repaired. Get it, for the price you can't go wrong!