I've been looking over the Cooling Fan Roundup 2012 sticky a lot lately trying to decide what fan I want to go with to load up my case with. It's a great resource, no doubt, but there's one thing it's missing which I think would be handy: a chart which clearly demonstrates which fans have the best airflow to dB ratio. That's what we're really all after, right? Many of the fans in the list are high-powered PWM fans which most people are not going to be running at full speed, so what really matters is their airflow in relation to their dB level.
So I decided to put the numbers in a spreadsheet and find this out (only did 120mm fans for now):
Note that there are three sheets you can switch between on the bottom -- Velocity Tunnel Airflow, CFM, and RPM.
So it seems from this analysis that the Cooler Master Blade Master is the far and away winner in terms of airflow to dB ratio. It's so far ahead, in fact, that I'm a bit skeptical of the dB reading for that fan. If the author of that thread could comment on this, it would be appreciated.
Everyone else is invited to comment as well, of course. Thoughts?
First off, The roundup is fantastic! I am fairly new to aggressive cooling and I found it more informative than the several hours of videos and articles I went through before finding it. The tests seem well thought out and the explanations of why each test was important (or how they applied to real world use) were concise and clear. A tip of the cap to Ryan! To the OP of this thread, I also give a thanks. Your spreadsheet is a MUCH easier way of comparing the numbers than the tabs and split screens that I was doing.
Now, as far as your idea that the Cooler Master dB reading may have been off I had this thought, it seems there are 3 possibilities:
Option #1 - THE NUMBERS ARE SPOT-ON If so, the CM fan blows the competition away easily... Also, I hope for this one because I'm ordering 3 of them But, I see your point that its margin of victory is a little hard to believe and if it is that impressive then it seems like it would be talked about in forums as much as the 212evo was... So let's play Devil's Advocate...
Option #2 - THE MC dB IS WRONG - TYPO If the 21 is wrong, it seems very unlikely that it is just a flat out wrong number pulled from thin air or that the test equipment just decided to go off the rails for that one test. If there is a mistake then what seems the most likely is a typo-style error. What if that 21dB was supposed to be 31dB?... A simple typo on one entry (that was then copied and pasted into charts and the rest of the analysis) would certainly be an understandable mistake after putting 36 different fans through hundreds of tests. ALSO That would put the tested score within 1 dB of the rated dB level advertised by MC.
Option #3 - THE MC dB IS WRONG - TEST FAILURE If the 21dB rating came from a more random recording error than I proposed in option 2 or if their was some failure of testing setup or hardware, then the data for the MC 120 is nearly useless. But his tests seemed solid and there don't seem to be any other big discrepancies, so I am betting against this one. Though admittedly outright error is always a possibility... we aint none of us perfect!
MY PERSONAL CONCLUSION:
If there was no mistake then the CM clearly had the best ratios, period. If there was a typo-style mistake and the MC fan should has been 31dB... Then it still would take first prize on your spreadsheet. It would still be first place in both unrestricted and restricted airflow speeds, a close second in unrestricted CFM and first place again in restricted CFM. So if it were 31dB the victory wouldn't be as crushing, but the final answer would still be the same. Unless that reading came from a complete failure of the testing system, then the Cooler Master is the fan you want for your chosen ratio hunt.