Humans hear frequencies from 20 Hz up to 20,000 Hz. As we get older, or exposed to loud sounds which damage our ears (such as loud work environments, rock concerts, listening to loud music, etc.), the upper limit decreases.
An online Hearing Frequency test helps you benchmark the highest boundary of your hearing. If you can't hear any of the high frequencies played back during a hearing frequency test, don't blame your speakers too quickly.
An extended high frequency audiometric test can be seen as an audiophile-grade hearing test, assessing the very last octaves of our hearing and the frequencies that we are supposed to hear when we are young and in good health. Since regular audiograms produced by audiologists do not cover those frequencies, this test is highly valuable for us audio enthusiasts.