You guys better believe it, but a lot of people and including stupid audiologists tend to think that you don't need 8-20khz. But if you think about it, come on! Are we that stupid to think that mother nature want to waste energy on nonfunctional useless cells? NO WAY . And we gotta remember the number one rule, that mother nature designs our body to be lazy...so how is it possible that 8-20khz is useless if mother nature wants our body to conserve energy and be as lazy as possible. So today I talked with a professor. And he said, the high frequency are extremely important in the spatial cues. The reason why people think they are useless is because they are unconscious of the fact that these 8-20khz are functioning everytime to help us identify where the sound is coming from (perception and localization of sounds). in other words, if they are DEAD, staarting from 20khz and going downward, we less sublety in our identification of where the sound is coming from. That's why you have people in their 70s who can't discriminate multiple speakers in a noisy room. Put them in a quiet room with one speaker, then can hear fine given that 250-5khz speech range is audible. So yeah! He also suspects that these 8-20khz helps somehow protects the cochlea by assisting in something something, i don't know, but it is extremely important.