spec * SFF21D -> 800 rpm, 33.5 CFM, 8.7 dB, 12 V, 0.1 А; * SFF21E -> 1200 rpm, 49.0 CFM, 20.1 dB, 12 V, 0.15 А; * SFF21F -> 1600 rpm, 63.7 CFM, 28.0 dB, 12 V, 0.2 А. http://translate.google.com/transla...&hl=en&ie=UTF-8&oe=UTF-8&prev=/language_tools wow..8.7 dB but errr i cant be bothered coz it cant blow a mosquito..but its really for silent freaks
Better to get the 21F and run it at 6V to get the same result, but have extra performance to spare when needed. Cheers Olle
I bet it's just the motors that differ, which in turn provide different speeds at the same voltage. Since everything else is the same and performance/speed thus is directly proportional to the voltage (within limits) then a voltage adjustment is all it takes! (The noise is proportional to the speed^5.) Cheers Olle
Not really. Even motor generates noise on its own, regardless of fan speed. So noise is not proportion to the speed, especially at very low speed. Fan turbulence is not the major factor anymore. Instead of the noisy whirling noise, the motors generate noises like 'tik tik' etc.
You're correct of course, but that doesn't allow for a correct assumption of engine and bearing noise at other than rated speeds either... Cheers Olle
seriously..i dun have a clue wat u guy toking wen i shop for fans jus see the cfm n dBa rating..tats it
i duno much about cfm n dba..i just do it the old fashion way, physically testing it out.. e.g. plug-in fan, wahh! not bad not bad, very strong wind, ok i buy.
Perhaps I should get my act together and write that fan and cooling guide I've been planning for so long... That should explain the basic physics involved as well as how to think when planning your computer cooling solution. (Like why it's better to add than remove fans if the objective is to make the rig more quiet. ) I've spent quite a while studying this matter. University grade physics (dynamics, acoustics, electronics and thermodynamics are the sub-branches that mostly apply here), empirical experiments and reading/comparing fan specifications. Cheers Olle
my Scythe Ninja came with a silent 120mm fan. rated as....... Fan Noise Level: 23.5dBA Air Flow: 46.5CFM Fan Speed: 1200rpm http://www.scythe-eu.com/products/cpu/ninja_plus/scnj-1000P.php looks like it's a bit lesser CFM and more dB compared to the SFF21E. * SFF21D -> 800 rpm, 33.5 CFM, 8.7 dB, 12 V, 0.1 А; * SFF21E -> 1200 rpm, 49.0 CFM, 20.1 dB, 12 V, 0.15 А; * SFF21F -> 1600 rpm, 63.7 CFM, 28.0 dB, 12 V, 0.2 А.
