Quiet fan for little money

I bought this fan to incorporate him into my Lenovo Thinkpad Advanced Dock Type 2503 as the original fan was much too loud. Before that I had the Advanced Mini Dock in operation (which had no fan). Since the dock is on the table and the fan is about 60cm away from my ear, it was important to me that he is very quiet.
According to the description of the fan has a sound level of 24 dBA. I can only say that it is indeed audible but not as disturbing as the original Sunon fans (MagLev KDE1206PHV1). Of course, you could have to solder a resistor in the cable, but that it was not worth it to me.

Conclusion:
broadly the fan is realtiv quiet, but not ignored. In complete silence you can hear him already much (if running at full speed). The volume is comparable to the rotational noise of a hard disk (quiet but constant), so to a large piece of 36dBA quieter than Sunon fans.