SilenX is very cheap low quality fans. They claim they are quiet but in comparison to a Panaflo, Acoustifan or Nexus they cannot compete.
As for 14dba on that SilenX fan i highly doubt it. YOu might get more noise out of the electricity flowing through your house and computer.
As for the original post... well as everyone said, its Thermaltake. Thermaltake MUST take their acoustic reading from across the room or something, because they are no where near that quiet. NO WHERE NEAR.
-Kevin