From Rivendell Wiki
Before you start loading any audio onto a new system, you need to make a choice of what sample rate you are going to use. If you haven't already made a decision, the time for this choice is whilst you are configuring the server and workstations. Why should I do this you may be asking. Why can't I choose later on once I have everything up and running. Well, it would be worth looking at the reasons for using 44.1k or 48k sample rates.
44.1k is the sample rate that is used on CDs and most mp3s.