Science aside, Cooler Master's specs are usually fishy. For example, I remember having their 200mm fans a while back. The spec sheet claimed 19db of noise, which is basically inaudible during the day. But they certainly were not silent. I would have put them at 30db at minimum running on 12v.
As for the fan, I don't actually believe it has 3.9mm H20 of static pressure, especially at only 2000rpm. I've tested quite a few fans including Gentle Typhoons, multiple Corsair fans, San Aces, other coooler masters and etc, all with lower static pressure ratings, yet all with more pressure than the fan the CM units come with. You don't need a fancy air chamber to do this, can just use your hand on open air or on the other side of a radiator.
Anyway, the evo and 212+ are great performing and the fan is fairly quiet.
The 212+ is the successor to the 212 Evo.
Other way around. I had the 212+ when the evo was not yet released.