Output Noise

We used a high quality CEM-8852 Sound DB Meter that is installed 50 cm away from the NAS for these measurements. The ambient noise in our lab during noise measurements was below 30 dBA.



Under normal conditions, the KD20 will mostly operate in fanless mode. In our case, the installed HDDs registered a maximum operating temperature of 55°C after several hours of use, at which point the fan spun up at initially very low speeds. The only problem here is that we sometimes noticed severe vibrations caused by the HDDs' operation, which led to significant noise output. Some rubber mounts on the trays would easily alleviate this problem since the rubber feet the KD20 stands on apparently cannot take care of this issue by themselves.


According to Shuttle, the fan will never turn on when the temperature of installed hard disks is below 55°C. In case of higher temperatures, the 70 mm cooling fan starts spinning at low- to middle speeds to keep the system quiet, and the system shuts down instead of increasing fan speeds once the HDDs reach 60°C. This sounds really strange and could lead to data loss, so we would highly prefer the fan to operate at full speed instead. Nevertheless, the KD20 never shut down due to the HDDs overheating during our highly stressful tests, or for any other reason for that matter. You see, its thick aluminum housing plays an active part in moving the heat out of its internals, which helps the small fan.

Output Noise Comparison Graphs

The following graphs show the output noise of KD20 in comparison to other units we have tested in the past.



The KD20's semi-fanless operation makes it the quietest NAS we have ever tested during normal operation; however, this facet causes the HDDs to reach unprecedented temperature levels during normal operation. To drop HDD temperatures, we would definitely prefer a lower temperature threshold for the fan to operate.