For those of you who skipped the setup page, note that the sound pressure level of the basement where these fans were tested is about 30.5 dB(A). Fans making this much noise at 10cm have an adjusted SPL of 10.5 dB(A). So a reading of 11 12 dB(A) is as quiet as this setup can measure. That means that some fans can be significantly quieter, but still have an adjusted SPL of 11 - 12 dB(A; so some of these fans are quiet indeed too quiet to measure.
A chart like this allows you to first decide how much noise you can tolerate, and pick the fan or fans with the greatest output.
Note that the numbers following the fan names represent the average RPM observed.