I think that road noise is a little complex issue.
It has to do with tire hardness, tread design, and the surface you are riding on.
-Take snow tires (if you have ever driven on them); that's the gold standard for road noise. Don't you often hear the road noise from a big truck or 4x4 passing you on the highway.
-It's not simply tread depth; as I have a set of Kumho SPTs. They have very little tread design, are a softer compound that grips like hell; but, is also noisy without a lot of tread! Problem is, with lots of rain or ice - they are terrible!
-If you go to the TireRack.com site, you get a lot of owner feedback on the tires, that usually note the noise level.
-I would assume that a hard rubber tire, with lots of tread, and the tire pressure high, and a grooved concrete surface would be the worst case scenerio for noise.
-This year (the third on the Kumho's) I really noiced the noise when I took the OEM Goodyear's off after winter.
Soooooo - I'm not all that unhappy with the BadYears! They are fairly quiet on bothe the na and turbo