Review on 🤫 Noiseblocker NB-BlackSilentFan XM2 40x40x10mm: Silent Fan with 3800RPM, 14 dBa Noise Level by Sean Davis

The noise blocker fan did what it was advertised to do. Works well and is almost silent. I wanted to use it to cool the heatsink over the hot end of my 3D printer and provide adequate airflow for the vent to cool the parts on the underside of the fan shroud. The fan doesn't advertise that it has enough power for my application, so I can't fault it for being underpowered. If I was just using it to cool the heatsink it would certainly work as my heatsink doesn't need much airflow to keep it cool. But I was a bit disappointed with the fan's modest airflow, hence the 4 rating. I ended up using an old 40mm computer fan that I never threw away. The old fan was surprisingly powerful, noisy and vibrated. I installed it with a 100 ohm resistor and suddenly became quite civilized. He settled down and slowed down just enough for what seemed like perfect airflow. It even almost stopped vibrating. Vibration is the last thing I want to add to my 3D printer, but after finding a reasonably powerful and quiet 40mm fan I was frustrated enough to use the old one. So my experience can be useful for someone. Try an old noisy fan and run it through a low value resistor. You may be pleasantly surprised.