As I was out riding today I was wondering if some helmets are quieter than others. By this I mean the amount of air noise.

I think you would have to be moving pretty fast before it became a factor. I know that with my motorcycle helmets air noise doesn't become an issue until you hit 40mph+. At any rate when I do move faster than 30mph on a bicycle its not the helmet, but air moving past my ears I notice the most.

It's turbulence that you're hearing, not just speed. Try these: https://www.cat-ears.com/

I find that it's much quieter when I ride wearing a balaclava, which covers my ears completely.

TT- Is your current helmet a MSR? (Let's see how many old guys remember the noise that it's vent holes made. As you changed your head's position the pitch would change.)

My real reply is that i never noticed much noise with any helmet after the above mentioned one (which was based on a rock climbing design. If you got up to the speed where it made noise you were moments from hitting the valley floor). Andy.

Normal road and mtb helmets end some distance above the ears. The large majority of the noise is air going past and over the ears. The helmet straps in front of the ears can affect this to some degree. Keeping the flat against your head's temples, usually under the temples of any glasses, can help a bit.

Jeff, Thanks for the link about Cat-Ears. This product sounds like it will tahe care of the problem.
As for the speed ,I was only riding my hybrid yesterday because of road salt so the speeds weren't too high but the headwindalso played a factor in the noise.

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.

Had a Bell Sweep for several years, and it was well ventilated but noisier than anything else I'd used. Finally replaced it with a Volt--that one's a lot quieter and it seems to channel the moving air closer to the scalp.

So, yeah, I think different helmets make different levels of wind noise.

Some helmets are noisier than others. After a while, it either drives me crazy or I used to it.