Good link, It's been years since I looked at it. I applaud the disciplined test prcodures and the amount of work that took.
It's a shame my favorite Cooler Master Excalibur did poorly on the noise test.
They, like most, test the intake noise from 6" away. I use it for an exhaust fan, so they are testing the wrong end for me.
The Excalibur is good for radiator Push, as it has good static pressure. As I move a second one in place for Pull, I notice a ringing as it gets close. A wire ring finger guard breaks up that resonance. The resonance must be due to the bend (double pitch) of the blade. A wire ring finger guard breaks up that resonance. I saw a Noise blocker with a wire ring guard, is this typical for them?
Right now I'm using 1 of the Excalibur to replace 2 fans on the Antec H20 920. Also for the Thermal Take Water2.0 Pro. Both of these are double thick (~48mm) 120mm radiators.
The TT Water2.0 Pro stock fans are nice, when vertical. Move that rad horizontal and these fans vibrate, and ring a bit more. If I unplug one fan the noise drops. (I kept the 12v out of the results by using different cables from the power supply.)
I played with different fans on those rads. Generally, adding a second fan slows down the first one about 50-100 RPM, as reported by the mother boards monitor. The Pull is more affected than the push and gets more noisy. The extra thick rad should eliminate air interference patterns, I think. A fan shroud (gutted shell of an120mm - 25mm thick) seem to help with some.
So some things are not covered.
1. Noise measured for fan intake and exhaust.
2. Noise for Fan mounted in radiator Push and Pull.
3. Noise and vibration for vertical, horizontal mounting air flow up and down.