Here's my test. Grabbed a vocal line, saved it as midi in melodyne editor. Brought it into biab, transposed it down 12 semitones (I think) and changed the patch to cello.

The midi file didn't line up at all with the vocal line, though!!! Not sure why, might be user ignorance or maybe I didn't set the tempo correctly -- just a test, though.

I would have to be "more solid" on my vocal line to expect excellent results, I expect.

http://www.soundclick.com/bands/page_songInfo.cfm?bandID=551052&songID=13038136


Now at bandcamp: Crows Say Vee-Eh @ bandcamp or soundcloud: Kevin @ soundcloud