i think you need a nas. any basic nas would do look for a drive with at least 3 tb and make sure it supports drives that are bigger then 3tb. make sure it has 2 drives. a lot of units like WD and Seagate only ship with one drive. some nas units are set up at the factory to be 2 separate drives so you will have to reformat it as a raid . like a readynas 102. anything on one drive will be cloned to the other.
they are very quiet.
a couple points about nas is
get a nas with up to date firmware and support. they changed time machine a couple versions of os x a while ago , and you need an up to date nas so it works with the new time machine
even a really old ready nas duo like the one i own works with new time machin, because netgear is a very good company that regularly updates their firmware. but the processor is slow and it cant run plex and it has a 2 tb limit
itunes server. some nas can be their own iTunes server. but this might be limit playback to iTunes running on the computer, and not iOS devices or the apple tv. so you will probably have to run iTunes on a mac to serve whats on the nas
a lot of people likes plex. a lot of units can run plex on the nas itself ( primarily devices that use intel processors ) , but that won't work with anything you bought from iTunes that has drm
some older nas units can only support 2 tb or less