The noise levels of the drives were measured in a soundproof box at a distance of 10 cm; both when the drives were idle as well as during a random workload. Note that the numbers should be interpreted as follows: everything under the 30 dB(A) threshold is essentially inaudible at a normal distance. Everything under 40 dB(A) is as quiet as a whisper at a normal distance. Drives that exceed the 40 dB(A) threshold are clearly audible.
The IronWolf Pro is the second quietest drive in idle and when active it is the most silent drive.