I found a D-LINK ShareCenter DNS-327L review over at Expertreviews. This D-Link 2-bay NAS is an inexpensive two bay NAS with passive cooling. Passive cooling, of course, makes this NAS nearly silent. The only sound is that of the hard drives you use in the NAS.
Performance is fine for large files, so the NAS should be ok for normal media (music and video) sharing. Performance was not so good with small files:
We fitted the DNS-327L with two 3TB WD Red hard disks and tested the DNS-327L’s performance in JBOD, RAID 0 and RAID 1 configurations. Whether configured as JBOD and RAID 0, the NAS was fast at copying large files, but much slower when at copying small files. Small files were written at 11.5MB/s and read at 18.5MB/s, while large files were written at 80.7MB/s and read at 71.1MB/s. As expected, performance was noticeably slower when the NAS was configured as RAID 1. Small files were written at 7.6MB/s and read at 7.8MB/s. Large files were copied far faster, with write speeds of 56MB/s and read speeds of 60MB/s.
Overall, it looks like if you need a nearly silent NAS with good media file serving possibilities, you should check out this D-LINK ShareCenter DNS-327L review.