Try this? Amazon.com: Noctua 40x10mm A-Series Blades with AAO Frame, SSO2 Bearing Premium Retail Cooling Fan NF-A4x10: Computers & AccessoriesOK so I need to figure out something. My main 2P workstation is 34.8dba even with a C2550 fan going next to it right now. I fired up the 8-bay and it was running around 47.6dba. With 16x pin connectors and 4x SATA power connectiors, there is little chance I am going to re-do this wiring. Need to find a solution.
I'm assuming you're running SSDs which presumably don't dump out nearly as much heat as hard disk drives.
I bought a Noctua Redux 80mm for my 5 in 3 NORCO thing, and it quieted the hell down. Had a delta fan in it before.