Hello Christian,

   CH> I'd like to make this box a bit more silent...

Switch it off?  :-)

Seriously though, I have been giving thought to replacing
conventional ball-bearing fans on several machines with fans
that use magnetic levitation (maglev).  They are supposed to
be quieter and last even longer than ball bearing fans. They
sound as though they would be well suited for a machine that
was on continuously.  I should probably test this on some
non-critical machines for a while.

- Andy Ball