This is a good question that I�m glad you asked as it has been one my mind lately. I�m not very good with the SYNCHRO button myself. I mainly use it for endings when none of the �canned� endings work for me.
I�d like to use SYNCHRO for songs like �oye com va� that have important breaks during the course of the song. But when I try to use the SYNCHRO button the results sound very choppy.
Any tips?