9db reduction in noise over their standard tire is a big amount. 3db is minimum difference a person can typically hear. In audio world, takes double the power for each 3db. IF these are 9 db quieter than say Hankooks, that will be noticeable. Imagine that the Genny noise level rated by Car and Driver is around 67db at 60 or 70mph, that puts the car at unde 60db at speed.. Now, depends on how Conti measure the sound. If it is "net" inside the car reduction, this will be huge.. If it is measured from outside, the affect will be lower "net" sound pressure reduction inside. Because the car itself already reduces whatever sound from outside the tires make. They are very vague on the claims. And the tech sheet does not have specs, only safety, storage and shipping info. Still looking for a real data sheet with measurements, tread depth, and whatnot. No matter what, I bet we will be able to hear the difference. The Genny is great at taking out wind, and other car/truck sounds, about the only thing that gets through is tire noise. Reduce that by this much, should be easy to hear. A lower sound level.