Shuttle systems can be very loud, however, they are easy to make quiet.
Replace the PSU fan with something like an ADDA ball bearing fan, and then replace the 80mm fan with a NoiseBlocker or even Antec Stealth fan. One is plug-n-play, the other requires you to open the PSU, cut the wires,
and solder in the new fan. Very easy to do, and makes a HUUUUUGE difference.
Cheers,
Josh