Not to start a long discussion, but just wondering if anyone did any kind of diy-project on sound proofing the ventilation system.

I usually observe that when i rechange filters the db significantly drops to a bearable level - which is much more relaxed, the laser even being more noticable than the ventilation system.. When the filter does its work and saturates by time the loudness obviously increases a lot again..

Is there anything you guys (that have the laser and the ventilation in an office space and not a seperate room) do to decrease the volume of the ventilation system?

Thanks + Best,
Steffen