Originally Posted by
Metzinger
I'm sure the wind buffeting your ear canals is a far greater factor.
No, he is right, the helmet does make quite a bit of noise... especially where the wind hits the straps that go down on either side of your face.
I ride both with and without a helmet (from time to time) and I really notice the difference.
If I didn't believe in the potential benefit of the helmet, I would discard it due to the noise that actually blocks being able to discern some traffic.