Originally posted by RMepstead:
Great but what if they are in different keys?
then it will sound like Les Dawson's piano!
Transposing the sequencer or live play is extremely simple on the KN, mostly it consists of finding the transpose button on the panel.
Alternatively if you can only play in a specific key, a professional editor like Audition can change pitch of the audio without changing the song length over a couple of semitones with very little effect on quality, cheaper programs being spectacularly unsuccessful in that respect.
However I would say the whole point of playing along with karaoke audio like the Sunfly dvds is you have the exact song backing so are accompanying e.g. Nelson Riddles' original arrangement played on real instruments rather than a repetitive backing sequence, so transposing would seem at odds if authenticity is that object. In any event nothing to do with SD audio syncro.