Are those mask fans noisy?
Entire Team uses them for Scenario play.
Not noisy, not at all.
Infact like most noises (like the sound of the blood pumping through your ears and face right now!) after a few minutes of that sound being continuous your brain simply just doesn't process it anymore and when people say you cannot hear it. They are literally saying their brain no longer considers the sound of the fan important and therefor does not bring it to your conscious attention.