GameStooge relates the experience of playing The Beatles: Rock Band at E3.
Excerpt: "The biggest gameplay change is that there are three vocal tracks, rather than just one. If only one person sings, the game will automatically track which key the player is singing in. However, if more than one player is singing, they can make bonus points if they each take a track for a "Double Fab" and a "Triple Fab". Players can sing in any key they like, but the bonus is only awarded if the players take different singing roles. Another major gameplay change is that playing on Easy is automatically a "no fail", allowing novice players to rock along."