There was a product a few years ago that was a little plastic wing that was attached to the helmet chin strap in front of the ear. The idea was to create lower velocities behind the spoiler and reduce wind noise. This can also be accomplished to a small degree by turning the strap in front of your ear around so wind is deflected away from your ear. It was difficult for me to tell if this really worked.

I think most regular riders just become used to the higher noise levels and are only reminded of the issue when we get a good tail wind (or forgo a helmet for a knit cap) and are amazed at how quiet it can be on the road.