To measure noise levels we place our sound level meter approximately 1 meter away from the chassis and 4 feet off the ground.
KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet take off/Gunshot (close range)
160dBA – Instant Perforation of eardrum
At full speed the fan is definitely audible and we would not want to keep it running at that speed continuously.
Under PWM conditions the fan is barely audible and never intrusive. All in all, we were pleasantly surprised by these results.