Sorry for the long story. Perhaps grab a beer.
I've come a long journey from having almost silent media / storage pc - 4x 2TB EARX WD greens in a Fractal Design Mini Define (comes with sound deadening foam and basic silicon isolation for the drives), Enermax Pro87+, passive gfx card, passive cpu cooler, and a single undervolted intake fan.
Disk failed, couldn't get a matching replacement - so thought it was time to have a NAS rather than running softraid myself etc etc
Bought a Netgear RN314 NAS - Out of box, transfers drive vibration really really well.
No isolation options. Single cooling fan is OKish at low RPM, as long as your drives don't run hot. Bleeds terrible amounts of spindle noise out the front, no muffling on the air intake path - but let me get to that point and what I am trying to do now.
So turns out the EARX Greens are bloody brilliant cool running drives, with very little spindle noise and a solid seek noise that can be managed through decoupling.
I should have just "found" a couple more EARX drives, but I didn't so now I have a collection of disks (which I need to sell before my wife discovers - story for later
3TB 5K3000 Hitachi disks, OMG it sounds like someone is using sandpaper on the platters. Also they run hot, really really hot. So of course the NAS runs up the FAN to compensate and so much noise my ears are bleeding. So I think, 2.5" disks ... I don't really need more space than 2TB a slot.
Seagate Momentus 2TB ... wow, they are several times noisier than the EARX drives! Sure they run really really cool, like 31 deg C with the fan in the NAS still slow moving, but the spindle noise is driving me nuts.
So my crazy idea is to encase the disks with something that will transfer some of the heat (perhaps this isn't even an issue), and muffle the spindle noise. Because they are 2.5" disks in 3.5" caddies, I have space to spare, although the attachment point is hard to the back and side, so the SATA / Power lines up with where the 3.5" disk would have them.
I found this http://www.quietpc.com/smartdrive-proof25
but they are crazy priced, but I guess this is kind of what I want to do
Any ideas to silencw my 2.5" disks or NAS somehow, cause I really like the Netgear ReadyNAS OS and size of the device