Most common is for people to lose the high frequencies with age. Low frequency hearing loss is also associated with some kind of brain trauma like stroke, CVA, TBI. I know a guy who has lost almost all his high frequency range down to about 1kHz. When I ask why he has the treble up so high to the point of essing, he says he want to hear the clarity of the voice. And, he is tone deaf with low frequencies, as he can't hear the difference between a full note on some bass lines. Anyway, low sub woofer frequencies below 40Hz is often very difficult to hear even at moderate volumes. Some say below 40Hz is where we feel the bass vs hearing it. If you can make out the difference between notes down to 60Hz, you're not tone deaf. Bass frequencies on 4 string bass rarely use anything lower than 60Hz.