As the A#1 question Cool Components' gets asked, are the fans quiet, we felt it appropriate to create a separate page to discuss the noise related to cooling and venting equipment. One may think noise is noise, fans just make noise but lets just break down the noise and a few elements of noise that is encountered.
First, it should be noted that probably one of the reasons this is the top question is due to many companies over the years (decades) marketing their products as quiet, silent, whisper quiet... when in reality they were 747 loud! This has done a disservice to not just companies like Cool Components but also to newer fan technologies and advancements. Should people still be skeptical when companies claim silence, unfortunately the answer is a very resounding, YES!!! It is just an educated guess that since most of these companies aren't really cooling companies, they are rack manufacturers and others who just don't give cooling and the fans they use proper attention and thus they base the fans they use more on what is more readily available versus what is most appropriate.
Very Important Note: Most likely if you are on this page you are concerned about noise but if noise is not a huge concern and more airflow is your desire, CCI offers High Velocity fans which spin faster, move more air and thus, are louder. The point is not all applications require silence so this section is more dedicated to those that do require silent products. This includes most home systems as well as conference rooms, offices, lecterns...
Types of Noise
While most the question is very simple, is it loud or not, the answer may also be simple but understanding the why and how some fans are quiet and some are not can help differentiate between products that are and are not very quiet.
Airflow Noise. The bottom line is there is no magic fan that can move tons of air and be silent. The key is simply a proper balance between fan speed (rpm) and airflow (cfm). The very simple fact is that the faster a fan spins, the more air it will move and the more noise it will make. This noise is simply from the 'reaction' of air being aggressively displaced. Now one consideration with this is there are differences and advancements with things like fan blade design which can help reduce noise but honestly, it's not significant but at the same time, even 1db here or there can mean the difference between some people hearing the fans or not.
So the key for this section is very simple, to be silent you need a balance but also consider that there are also other factors with this such as, a fan unit venting a cabinet in a home theater has a different threshold then say a fan installed in a rack in a closet. This is 100% the reason why CCI products focus so much on variable settings, either through controllers or simply setting the voltage and thus fan speed. In creating and facilitating that 'balance' with different applications, CCI deploys fans that are quiet yet effective at 5-7V or can be run more aggressively at 9-12V. What most everyone else does is kick down the voltage and provide no option to run more aggressively thus not providing for a greater range of airflow.
Motor & Bearing Noise. The biggest shortcoming and thus advantage to CCI products is the bearing type. Every other company uses ball bearing fans which ball bearing fans were a great advancement of sleeve bearings decades ago but it makes no sense that technology based companies are not keeping up with technology. Today's more advanced bearing systems include technologies like magnetic and fluid bearings. CCI has always used magnetic bearings and the difference is that ball bearing fans from day 1 begin a linear progression of getting louder and louder. Usually just within a few months can begin to hear the bearing noise and usually within a couple years most people want to replace the fans due to the noise. Magnetic fans will stay quiet on day 1 or year 5 and beyond. The technology simply makes sense where a magnetic field is created to essentially 'float' the spindle and essentially there is no contact so no wear.
One other problem with bearing and fan noise is it can usually be at an octave that is not only audible but can venture into that annoying frequency range.
For the type of fans used in most electronic cooling, the motors are fairly comparable as long as it's a quality fan. Most fans have brushless DC motors and capable of lasting a long time.
Vibration. This is our last and perhaps most annoying source of noise from fan based cooling products! While the smaller fans, 60mm and smaller, usually do not create much if really any perceivable vibrations, the larger fans can most certainly create a chain reaction of vibrations which most likely will be very annoying to anyone in earshot of the unit. One way CCI isolates vibrations is by using custom made silicone fan isolation mounts which coincidentally, also makes reversing the airflow a breeze (pun intended). The mounts provide for easily pulling the fans off, reversing them and re-fastening.
Bottom Line with Fan Noise
Use a Quality Fan that Deploys a Newer and far Superior Bearing System