I have created my own scale for helmet "quietness"
I consider a helmet to be quiet if you can listen to a radio station or a talking book and understand what is being said without it sounding "loud"
My Schuberth C3 fits that up to about 80km (50 mph) effective wind speed. ie 80 k in the calm, 100k with a 20k tail wind etc.
After that I can hear music if turned up
anything over 115k the music has to be too loud to listen and enjoy.
After 120-125 I need ear plugs
Lucky for me I generally travel at about 105-110 k so unless I am pushing a head wind I can generally hear my music nicely but could not listen to a radio station
That is on my F800GS with the standard windscreen and a laminar lip.