I think you need to understand hearing loss is not only related to the audible frequency range but also the SPL of a given sound.
Our ears do not perceive low and high frequency sounds as well as they do sounds between 500Hz and 4kHz. The faintest sound a young person with normal hearing can hear at 2.5kHz is 0dB SPL. At 20Hz, the sound needs to be much louder at 72dB SPL in order to just faintly hear it. The degree of hearing loss one has refers to how loud you need sound to be before you can hear it.
You may find these sites of interest;
Use our online hearing test to confirm your hearing. Our unique calibration assures higher confidence in the test results than any other online test.
www.audiocheck.net
auditoryneuroscience.com
JSmith