I think I can still make out something at 19KHz, but I might be imagining it. So, 18 for me. Don't care much anyway, music is a bit lower.. :) Plus I'm starting to feel lucky for not hearing every electronic whine and buzz around like some of the previous posters.
For a couple of years in highschool I used to burn out cheapo headphones from listening at extreme volume. I feel really sad for my ears just thinking about it.
Edited by zmd - 6/9/11 at 3:05pm