With SpeedFan fan scaled with me wonderfully between 470-1470 rpm (0-100% PWM).
So "inaudible" to "good performance at bearable volume".
I have a fairly quiet PC: only insulated notebook hard drives / SSD, very quiet BeQuiet! E9 400W PSU and a graphics card.
The cooling performance was no worse for quieter operation and the power consumption is okay!
The fan makes a high quality impression and also looks chic.
The next fan-new purchase I'll probably access at the eLoops again (with the replacement of an existing, silent, fan brand well - because of the price - usually should not be rewarded).