Rock Band 2 is a music video game developed by Harmonix Music Systems. It is the sequel to Rock Band and is the second title in the series. The game allows up to four players to simulate the performance of popular songs by playing with controllers modeled after musical instruments. Players can play the lead guitar, bass guitar, and drums parts to songs with "instrument controllers", as well as sing through a USB microphone. Players are scored on their ability to match scrolling musical "notes" while playing instruments, or by their ability to match the singer's pitch on vocals.