Output Noise

I use a Class 1 Bruel & Kjaer 2250-L G4 sound analyzer equipped with a Type 4955a microphone that features a dBA-weighted dynamic range of below 6 dBA and up to 110 dBA. All tests are conducted inside a hemi-anechoic chamber at 25–28 °C ambient, and the test subject is placed a meter from the sound analyzer.


The unit's fans are not noisy, especially in quiet mode, which is set in DSM. However, running the fans at full speed will probably wake up the neighbors.

Output Noise Comparison Graphs

The following graphs show the output noise of the DS1621+ and compares it to other units I have tested.



DBB fans are not among the quietest. Still, with the NAS operating normally, output noise will be below 30 dBA.