When you're considering a new helmet, one of the things on your mind is probably noise. When you're going down the highway at 55+mph, you have a lot of wind noise to deal with. And it's hard to tell what helmet is going to work better especially when everyone's ears, bikes and accessories are different. The bottom line is, you aren't going to find a magical helmet with so much wind reduction as to silence the world around you. You may have to take a couple extra steps to reduce the wind noise around you.
As a sportbike rider, I'm fighting not only wind, but a minimally faired bike and a lower windscreen. If you expect any helmet to completely silence your ride, prepare to be disappointed. After zipping around today on the back of my friend's Goldwing I discovered just how amazing a large windscreen and fairing could be!
I will say that I was pleasantly surprised by the added noise reduction my Schuberth provided on this kind of touring bike. My friend Mike and I were able to chit chat along the way to brunch (which was delicious, btw). I didn't wear my earplugs, and didn't even notice that I didn't have them in until we started across the bridge.
If someone tells you how quiet/loud their helmet is, make sure you ask all the questions and don't assume everyone is going to have the same experience.
And don't forget to make sure you're wearing the right size/fit, because there's nothing worse than a helmet that's too big letting in even more noise.