I never thought of it that way but it makes sense. My hearing is fine and I can pick out quiet sounds, far away sounds, high-pitched sounds, etc... But I always have trouble turning the sounds that comes out of people's mouths into words especially if there's other noise. It's not a focus issue, either. I'm probably just bad at hearing speech in those situations for some reason.

I have heard this[1] and my girlfriend (an amature musician) has worse hearing than me generally (subjectively based on quiet situations picking out very quiet sounds or high frequencies) but is way better than me in loud enviornments.

[1] http://io9.gizmodo.com/5839116/lifelong-musicians-can-unders...