Output Noise
I use a Class 1 Bruel & Kjaer 2270 G4 sound analyzer equipped with a Type 4955a microphone with a dBA-weighted dynamic range of below 6 dBA and up to 110 dBA. All tests are conducted inside a hemi-anechoic chamber with a noise floor close to 6 dBA and an ambient temperature of 25–28 °C. The test subject is placed a meter from the sound analyzer.
Full & 70% Speed
The speeds are high, so increased noise is expected.
Speed (Percentage) – Noise
I use a different setup to drive the fan for noise measurements, so there might be a difference in the readings of the Longwin machine, especially in the max fan speed reading.
P12 Max White
P12 Max Black
Pages:
The double ball bearing model is gone in the US. Arctic decided to change it to FDB.
I saw. I can no longer find P12 Max with double ball bearing, whether in the black or white version. That is, the black one is now FDB too!
Black: https://www.arctic.de/en/P12-Max/ACFAN00280A
White: https://www.arctic.de/en/P12-Max/ACFAN00293A
Note that the bearing is the same (double ball bearings) in both colorways. Is it the end of the double ball bearing?
I guess, the metal screeching at lower RPM caused a lot of complaints 😛
First of all, many thanks Aris!
Well, I was expecting bigger difference at lower RPMs. In the higher I expected very similar results, as it is, because the main source of noise, which covers other sounds, is created by a moving air mass that radiates a sound wave into the environment. And since the geometry of propeller is the same, there should be no major differences.
This 2nd DBB fan is not so disturbing at 10% (although it’s very near) as the 1st DBB (spike at 5 kHz). However, at 25% it is even more annoying than 1st one because of the harmonics/resonance, which starts between 2nd and 3rd second in the recording.
FDB has much nicer sound at 10% and 25% PWM level.
One note: I have one hypothesis as to why the 1st DBB has higher power consumption than the 2nd. The spike at 5 kHz reminds me of grinding/scraping metal on metal. The bearings may not be sufficiently lubricated, or the tolerance of the bearing balls is not tight enough … but its only a guess 😀
for sure there was something wrong with the first sample, since its peak RPM on the longwin were also off.