[wideminded]

I was assuming that if you have already lost all hearing above 8 kHz, this is not a good sign for your future ability to hear in the voice range. Perhaps this is not justified, although the person I mentioned earlier has deafness in her family.

[DB]

Actually I don't think that is true, but I could be wrong.

If you abuse your ears, the highs go first. Also with age the high end goes first.

Most people can't hear 18 kHz when they're in the 30's. 9 kHz to 18 kHz is one octave. While that isn't good loosing the upper octave of your hearing, it isn't very serious either. The biggest impact with be enjoying music which shouldn't be severe.