well, you only need one of them to be beatmapped.
find the BPM of the instrumental (use a free bpm counter or something). Set the master tempo to whatever bpm it is. Then load in and beatmap the acapella. Voila - they will both be in time!1!!
(
mugatu,
Fri 17 Nov 2006, 13:25,
archived)
I'll give it a go!11!
(
wefbhweiufhweiu party,
Fri 17 Nov 2006, 13:35,
archived)