Contributor TheBigFan used fan laws and sound equations to calculate the theoretical airflow and noise levels of 111 selected DC fans at reduced speeds, multiples and different configurations. This fascinating article sums up the thorough research and thoughtful analysis of a self-professed noise fanatic to identify the quietest fans that cool well. The data is downloadable as xls, pdf or zipped xls files. A very worthy addition to SPCR’s growing knowledge base!
ADDENDUM 3: gmJamez’s Variation >– March 11, 2003
Yes, this is turning into a real collaborative work. SPCR Forum member gmJamez spotted discrepancies and errors based on the use of incorrect data. Please see below (or click on the header above.) – Mike Chin
Updated Oct 18, 2002
Not long after this article was published, sharp-eyed reader Mark Thompson pointed out some errors in the tables created by TheBigFan. A few exchanges between author and reader ensured, the result of which was a new table of corrected data.
Here is the author’s note about the changes:
My table now represents the actual voltages you would use: 12V, 7V, or 5V, and includes many fans. I also fixed a few glitches in the formulas and formatting.
As Mike Chin emphasized note that these numbers are purely theoretical, and that I havn’t actually measured anything. Thus they can serve as a useful guide in determining the optimal configuration for you, but don’t expect the noise levels to represent what you’ll actually get in real life.
I got a pair of Papst 8412NGML fans a few weeks ago, which rate pretty well on my table, but to my untrained ear, I’d estimate their actual noise level in real life is about 10 dB higher than the stated noise level. I think this will be the case for most if not all fans.
Thanks for the feedback!
To my chagrin, I discovered recently that I had neglected to replace the original table. My apologies to all. The new table is now in place, in PDF and XLS (Windows Excel) format.
July 14, 2002 – by TheBigFan
This fascinating article sums up the thorough research and thoughtful analysis
of a self-professed “noise fanatic” to identify the quietest case
fans that cool well. After collecting specifications, fan law and sound equations
were used to calculate the theoretical airflow and noise levels of each
fan at reduced speeds, multiples and configurations. (We’ve identified the Comair-Rotron
website in our