I've never noticed the sound at high speed. They are pretty loud 10-15 or so mph then they quiet down...or the wind noise drowns them out.

I have a set on my tri/tt bike. I like them but the braking sucks (carbon rim). I've popped the front on my fixed and I like it for bombing around. Much lighter than my 36 spoke deep v. As has been said, if you aren't going fast enough they suck in crosswinds. I bonked one day this summer and had to buck a gusty head/crosswind for 25 miles on them. No fun.