Cryorig C7 - huge noise variance in reviews

[piokos]

I went through a dozen reviews of Cryorig C7 lately (and some user opinions).
While the temperature results are fairly consistent, noise findings vary from silent to noisy.
I assume few large review sites didn't get bad samples, so what is it?
Is there a quality problem with C7's fan?

I would like to believe it was an early manufacturing issue, but even people that bought this cooler recently are complaining.
Replacing the stock fan with a Noctua one (using a 3D printed adapter) seems like a standard procedure...

 

[EXCellR8]

Could be any number of things... how it got installed, what speed the fan is set at, case acoustic design etc. Most of these air cooler fans are manufactured by only a handful of OEM's so the chance of getting a faulty one, while it is entirely possible, is quite low. I've found that the coolers that throw air directly onto the CPU such as this one are typically a bit noisier than the ones that run the air parallel to the board anyway.

 

[UsandThem]

It could also very well be the equipment they use to test the noise levels. Some sites have true silent audio testing rooms, and professional equipment. I've also seen some sites use a cell phone and app in a regular room with noise to get their readings.

So things like that probably account for the wide variance in readings.