I was lurking around SPCR for many years, and finally decided to post here
. So, as the title says - I`m quite noise/hum sensitive and made everything to make my rig quiet as possible, but the next problem is this - the air turbulence/resonance - no matter if the HDDs are powered ( they are very quiet already and soft mounted ), when the case is opened the air resonance/turbulence fade away in room, but when the case is closed then the air resonance/turbulence occurs - it is not too much, but I can surely notice it - also if I turn off all the fans the air res/turb. is gone. I already dampened the inner top of case and both side panels with http://www.pcsilent.de/en-pd-be-quiet!- ... s-310.html and it noticeably helped dampen remaining vibrations and air res/turb, but not all of them. So - the question is this - is there any method/something to eliminate the remaining air res/turb ? Will some "conical" shaped foam help, like these ? : 
PS: This is my rig:
All Getle Typhoon are spinning ~750 RPM, also the two Noctua S12's are replaced with one GT on the bottom position now ( I dont have camera atm to make actual photo )