Project lead for The Beatles: Rock Band, Josh Randall, has said that Harmonix was set on three-part harmonies for the game, and worked diligently to make it happen properly.
“Originally, with [Rock Band] and with all of our games, we wanted to just create the ultimate party in your living room. And whenever we play Rock Band together, there are always extra people in the room. So we thought, “What if we just have an extra mic?”, Randall told Gamautra.
“But then, we thought about it more, and we realized that a big signature part of The Beatles’ music is the beautiful harmonies that they do, so let’s actually turn that into a real game element.
“We went through a really heavy prototyping phrase, figuring out, “Alright, how do we get multiple arrow pointers? How do you know what you’re singing? How do we do the scoring?” and all of that. We did really tight iteration, where like every morning we would meet and try out the latest version and tweak it to see how it works.”
Game’s out September 9.