Ipods and similar devices now come with WARNINGS because of how they can affect hearing!
The sensitivity differences are common with autism. I have the same.
BTW MY hearing isn't nearly as good as it was either. As for the what and HUH, with ME that has more to do with the other person mumbling, accents, and I guess maybe something like CAPD than anything else. Sometimes I figure it out JUST as I say HUH?! WHO KNOWS though! There is one person I know that mumbles, mispronounces, has a think accent, etc.... and I seem to be one of the few that can understand him.(I sometimes translate for our boss!) I even sometimes understand his phone calls.
As for the construction, etc... I guess even Aspies CAN filter! When I was younger, I had trouble sleeping at this one place that had wind up clocks. It took me over a year to get used to the valve I got for my heart, though nobody else can even hear it. SUPPOSEDLY, aspies have trouble with this, but I got over them.
Steve