A disembodied voice, should be calm and mellow, slow and precise speech but not dry and drab.  Give it a bit more of a professional energy and sound sort of excited. The general tone of voice is that of a lecture of sorts, or a voice being spoken over an editorial. This character is going to relay a lot of information. So it should be spoken by someone who has kind of a commanding voice but not so overly assertive but not too soft a bit monotone at times.