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 Barracuda Pro 12TB is pleasantly quiet in idle, but in many cases your operating system will turn the drive off completely after some idle-time. When writing the Barracuda Pro 12TB cannot be called very quiet, but it is not exceedingly loud. We often see that specific NAS-drives are more tuned on lower noise levels while with this drive we clearly see that the performance is the most important focus.