Just like to point out the obvious...
If you're running it passively, you have nothing making a noise, and therefore no need for a silent case to stop noise getting out because...well...there's nothing to make a noise in the first place...
Well I personally have all my fans running at 5v, and they're completely inaudible even without a silent case.
Well, if u want to hear zero sound, then u see the need of a silent case.
If this Fractal is open in the front side, the noise come out. And my head is exactly near there
What about the noise of psu, vga fan, hard drives?...
The R4 also comes in white if that by any chance tickles your fancy...
I assumed if you're going to the extent of no case fans or CPU cooler, you'd be using passive/semi-passive PSU, Solid state drives and a passive GPU.
If a case has only the rear out take fan spot open your going to have a bad time, how is it going to move air through the case if there are NO other holes....