In addition, it looks like they didn't like the sound of TY-14x samples they've had, in the couple of cooler reviews relevant. Dunno if it's just luck of the draw, changes over time, or you hearing things differently.
The stock fan's acoustics are average at 9V and above. The fan generates a dry, tonal hum that decreases with speed, but it is always audible at close proximity. At 7V and below, it is barely noticeable at one meter, and if enclosed in a good case, it should be inaudible. The measured noise level is very low for a fan of its size and speed, generating just 23~24 dBA at full speed and approaching our anechoic chamber's noise floor at 6V.
The HR-02 stock fan is the same model included with the Silver Arrow and Shaman. It is fairly quiet for a 140 mm model, producing only 22 dBA@1m at full speed, and almost inaudible at 7V while spinning at 730 RPM. It doesn't have great acoustics, though, as the motor generates some undesirable noise. Between 800 and 1100 RPM there is an audible hum with some slight clicking. Thankfully, at one meter distance with a case side panel running interference, it would be difficult to detect.
And on the other hand, the Phanteks (different test setup, as using a different heatsink):
Aside from our reference NF-P14 FLX, the PH-F140HP/TS had the best acoustics of the fans in this roundup, having a much cleaner profile than the latest offerings from Noctua. At higher speeds it sounded buzzy and turbulent as many fans do but at 900 RPM and below it was almost completely smooth, aside from a very faint clicking audible only at close proximity at 700 and 550 RPM.
Sample variance was minor. Of the three samples we had on hand, the white variant produced a slight tone at lower speeds while the black model was a tad whinier at full speed than the blue. The blue version used in our test had a superior sound though the other two were very similar.
And it's not all Phanteks fans.
Unfortunately the new Phanteks fan is considerably worse than the older PH-F140TS that ships with their flagship PH-TC14PE cooler. At higher speeds it's turbulent and buzzy. Starting at about 900 RPM, it begins to drone and produce an odd, almost ghostly tone which continues as the speed is reduced. The droning starts to transform into a less offensive humming sound at lower speeds but the tone remains, even at the minimum speed.