It could have been a very good, affordable fan with lighting. Moreover, the SickleFlow 120 ARB rotor design is efficient, at an excellent level, but all the good features are killed by one thing – an extremely noisy motor. It’s so noisy that a return trip from the factory output control would be appropriate. And it’s not just your everyday whir that you hear only from centimeters away. No one will ever miss this sound.
Results: Airlow w/o obstacles
Why is there a missing value sometimes? There may be more reasons. Usually it is because the fan could not be adjusted to the target noise level. Some have a higher minimum speed (or the speed is low, but the motor is too noisy) or it is a slower fan that will not reach the higher decibels. But the results in the graphs are also missing if the rotor is brushing against the nylon filter mesh. In that case, we evaluate this combination as incompatible. And zero in the graphs is naturally also in situations where we measure 0.00. This is a common occurrence at extremely low speeds with obstructions or within vibration measurements.
Thank you so much for this! I thought that I might have just gotten a bad batch with my CM AIO cooler. Although, in my case, it’s not rattling but an uneven hum that keeps going up and down.
And thanks to your other reviews, I ordered some Noctua NF-A12x25 today. That’ll hopefully solve that. All of my other fans are Noctua too and while not all the new and best, they at least produce steady noise.
Using Noctua NF-A12x25 fans will definitely solve the issue you’re describing. The sound of the tested Cooler Master fans can be perceived differently by everyone. It’s certainly not clean in terms of aerodynamics. There’s absolutely nothing wrong with your ears. 🙂
Yeah, I’m very happy with the A12x25s! Skimming the Noctua website also reminded me that based on their description, what I heard may have been that “beat frequency”. They of course took care of that with the RPM offset in their 2x package.
Using different motors to achieve different RPMs under the same PWM signal is indeed a clever trick to reduce noise while maintaining strong airflow and cooling performance. 🙂