The fans tested here were either provided by the manufacturers without preconditions or come from the editorial stock or were anonymously purchased in stores. None of the tests were influenced in any way by the respective manufacturer. The test results were communicated to the manufacturers for review and comment in advance in case of abnormalities or strong contradictions to the stated technical data, and in some cases, measurements were also taken with anonymously purchased retail goods.
We explicitly point out that our laboratory cannot and does not want to produce ISO-certified measurements. The test setups with and without radiators were designed by us to be as practical as possible, in order to capture all intermediate values in the respective speed ranges. The audio recordings were normalized to also transport the smallest nuances into the audible ranges. Therefore, it may well happen that the fans seemed louder than they are. For a comparison of the absolute noise emission of two fans, the measurement curve must always be compared.
The manufacturer information used comes either from the respective packaging or from the data sheets on the respective homepages of the providers. Since we have already found several printing errors and even completely incorrect information, these values should always be viewed with the necessary skepticism if they significantly deviate from our measurements. Moreover, more than once the product has been significantly changed over time without this being publicly communicated. In this case, we ask our readers for appropriate feedback if new contradictions arise.